The prevalence of mental disorders among homeless people in high-income countries: An updated systematic review and meta-regression analysis

Stefan Gutwinski; Stefanie Schreiter; Karl Deutscher; Seena Fazel

doi:10.1371/journal.pmed.1003750

. 2021 Aug 23;18(8):e1003750. doi: 10.1371/journal.pmed.1003750

The prevalence of mental disorders among homeless people in high-income countries: An updated systematic review and meta-regression analysis

Stefan Gutwinski ^1,^#, Stefanie Schreiter ^1,^2,^#, Karl Deutscher ¹, Seena Fazel ^3,^*

Editor: Vikram Patel⁴

PMCID: PMC8423293 PMID: 34424908

Abstract

Background

Homelessness continues to be a pressing public health concern in many countries, and mental disorders in homeless persons contribute to their high rates of morbidity and mortality. Many primary studies have estimated prevalence rates for mental disorders in homeless individuals. We conducted a systematic review and meta-analysis of studies on the prevalence of any mental disorder and major psychiatric diagnoses in clearly defined homeless populations in any high-income country.

Methods and findings

We systematically searched for observational studies that estimated prevalence rates of mental disorders in samples of homeless individuals, using Medline, Embase, PsycInfo, and Google Scholar. We updated a previous systematic review and meta-analysis conducted in 2007, and searched until 1 April 2021. Studies were included if they sampled exclusively homeless persons, diagnosed mental disorders by standardized criteria using validated methods, provided point or up to 12-month prevalence rates, and were conducted in high-income countries. We identified 39 publications with a total of 8,049 participants. Study quality was assessed using the JBI critical appraisal tool for prevalence studies and a risk of bias tool. Random effects meta-analyses of prevalence rates were conducted, and heterogeneity was assessed by meta-regression analyses. The mean prevalence of any current mental disorder was estimated at 76.2% (95% CI 64.0% to 86.6%). The most common diagnostic categories were alcohol use disorders, at 36.7% (95% CI 27.7% to 46.2%), and drug use disorders, at 21.7% (95% CI 13.1% to 31.7%), followed by schizophrenia spectrum disorders (12.4% [95% CI 9.5% to 15.7%]) and major depression (12.6% [95% CI 8.0% to 18.2%]). We found substantial heterogeneity in prevalence rates between studies, which was partially explained by sampling method, study location, and the sex distribution of participants. Limitations included lack of information on certain subpopulations (e.g., women and immigrants) and unmet healthcare needs.

Conclusions

Public health and policy interventions to improve the health of homeless persons should consider the pattern and extent of psychiatric morbidity. Our findings suggest that the burden of psychiatric morbidity in homeless persons is substantial, and should lead to regular reviews of how healthcare services assess, treat, and follow up homeless people. The high burden of substance use disorders and schizophrenia spectrum disorders need particular attention in service development. This systematic review and meta-analysis has been registered with PROSPERO (CRD42018085216).

Trial registration

PROSPERO CRD42018085216.

In an updated systematic review and meta analysis, Stefan Gutwinski, Stefanie Schreiter, and colleagues examine the prevalence of mental disorders among individuals who are homeless in high income countries.

Author summary

Why was this study done?

Homelessness continues to affect a large number of people in high-income countries and is associated with an increased risk of mental disorders.
To guide service development, further research, and public policy, reliable estimates on the prevalence of mental disorders among homeless individuals are needed.
Many primary investigations into rates of mental disorders have been published since a previous comprehensive quantitative synthesis in 2008.

What did the researchers do and find?

We performed a systematic database search, extracted data from primary reports, and assessed their risk of bias, resulting in a sample of 39 studies including information from over 8,000 homeless individuals in 11 countries.
We conducted random effects meta-analyses of 7 common diagnostic categories. Prevalence estimates were all increased in homeless individuals compared with those in the general population. Alcohol use disorders had the highest absolute rate, at 37%, with substantially elevated proportional excesses compared to the general population for schizophrenia spectrum disorders and drug use disorders as well.
There was substantial between-study variation in prevalence estimates, and meta-regression analyses found that sampling method, participant sex distribution, and study country explained some of the heterogeneity.

What do these findings mean?

The high burden of substance use disorders and severe mental illness in homeless people represents a unique challenge to public health and policy.
Future research should prioritize quantification of unmet healthcare needs, and how they can be identified and effectively treated. Research on subgroups, including younger people and immigrant populations, is a priority for prevalence work.

Introduction

Homelessness is recognized by the United Nations Economic and Social Council as an issue of global importance [1]. In high-income countries, around 2 million people have been homeless over the past decade [2]. In the US, the lifetime prevalence of homelessness is estimated at 4.2% [3], with around 550,000 individuals lacking fixed, regular, and adequate residence on any given night [4]. Patterns over time have differed by country, although homelessness has increased in many high-income countries in recent years, including in the US and UK since 2017 [2].

There has been an increasing recognition of the public health importance of homeless persons, with many studies reporting high rates of acute hospitalization, chronic diseases, and mortality [5–13]. Comorbidities increase these risks, particularly mental disorder comorbidities. For example, in a Danish population study, comorbidity of psychiatric disorders increased mortality rates by 70% [14]. Furthermore, mental illness among homeless individuals has been associated with elevated rates of criminal behavior and victimization [15,16], prolonged courses of homelessness [17,18], and perceived discrimination [19]. Mental disorders among homeless individuals are mostly treatable and represent an important opportunity to address health inequalities.

Information on the overall extent and pattern of mental disorders among homeless people is necessary to inform resource allocation and service development, and to allow researchers, clinicians, and policymakers to consider evidence gaps. The large number of primary studies, of varying quality and samples, means that systematic reviews are required to clarify and synthesize the evidence, underscore main findings, and consider implications. According to a recent umbrella review, there have been at least 7 systematic reviews with quantitative data synthesis in the past 2 decades [20]; however, most of them focused on individual diagnostic categories [21–24], examined specific age bands [24,25], or were limited to a single country [26]. The last meta-analysis to our knowledge that provided a comprehensive account of the prevalence of major mental disorders in homeless adults in high-income countries completed its search in 2007 [27], and since then, a considerable number of primary studies have been published [28,29]. Thus, we conducted an updated systematic review and meta-analysis on the prevalence of mental disorders among homeless people in high-income countries, and added the diagnostic categories of any mental disorder and bipolar disorder.

Methods

Search strategy

We searched for studies that determined prevalence rates for at least 1 of the following disorders among homeless persons: (1) schizophrenia spectrum disorders, (2) major depressive disorder, (3) bipolar disorder, (4) alcohol use disorders, (5) drug use disorders, (6) personality disorders, and (7) any current mental disorder (Axis I disorders in the Diagnostic and Statistical Manual of Mental Disorders [DSM] multiaxial system [30]).

We have updated an earlier review [27] that was based on a search for articles published up until December 2007, so we targeted new primary studies published between 1 January 2008 and 1 April 2021. We searched Embase via OvidSP, Medline via OvidSP and via PubMed, and PsycInfo via EBSCOhost. Additionally, we searched Google Scholar using a search query and screened all literature citing the previous review. Finally, we screened reference lists of relevant publications. Each search employed a specific combination of search terms designed to fit the databases’ respective syntaxes and thesaurus systems (S1 Table). Articles written in languages other than English or German were translated by professional translators. The protocol for this systematic review and meta-analysis has been published (PROSPERO CRD42018085216). We followed Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines for extracting and assessing data [31]. This systematic review adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement (see S2 Table) [32].

Eligibility criteria and study selection

Inclusion criteria were as follows: (1) homelessness status of study participants was validated by an operationalized definition or a sampling method that specifically targeted homeless population; (2) standardized criteria for the psychiatric disorders specified above, based on the International Classification of Diseases (ICD) or DSM, were applied; (3) psychiatric diagnoses were made by clinical examination or interviews using validated semi-structured diagnostic instruments; (4) for any psychiatric disorders except for personality disorders (where lifetime rates were used), prevalence rates were reported within 12 months; and (5) study location was a high-income country according to the classification of the World Bank [33].

Surveys that reported a response rate of less than 50% or exclusively sampled from selected subpopulations (such as elderly homeless, homeless youth, or homeless single parents) were excluded.

In order to assess all results from the bibliographic search process, researchers SS, SG, and KD each carried out a multilevel screening process independently from one another. Any differences between results were resolved by consensus between all the authors.

Data collection and quality assessment

Information from included surveys was extracted on study location, year of diagnostic assessment, operational definition of homelessness status, sampling method, diagnostic procedures, diagnostic criteria, professional qualification of interviewers, response rate, dropout rate, number of participants by sex, sample mean age, current accommodation of participants, sample mean duration of homelessness, and number of participants diagnosed with schizophrenia spectrum disorders, major depressive disorder, bipolar disorder, alcohol- and drug-related disorders, personality disorders, and any primary diagnosis of a mental disorder apart from personality and developmental disorders (i.e., Axis I disorders in DSM). If data regarding any of these categories were unclear in the published study, we corresponded with the primary study authors.

Each included publication was rated on methodological quality by 2 sets of criteria specifically designed to assess prevalence studies: the JBI critical appraisal tool for prevalence studies [34] and a risk of bias tool [35]. This process was carried out by SS, SG, and KD independently, and any differences were resolved by discussion.

Statistical analysis

Random effects meta-analyses and meta-regression analyses were performed on each diagnostic category independently—prevalence data for alcohol misuse/abuse and alcohol dependence were both entered into the single category of alcohol use disorders, in accordance with current diagnostic approaches. All analyses were done in R, version 4.0.4 [36]. The package “metafor,” version 2.4–0, was utilized for meta-analysis and meta-regression analysis, supplemented by “glmulti,” version 1.0.8, for multivariable model selection and “mice”, version 3.13.0, for multivariate imputation [37–39].

Prevalence estimates were transformed on the double arcsine function in order to avoid variance instability and confidence intervals (CIs) exceeding the interval (0 ≤ x ≤ 1) in which prevalence proportions can be meaningfully defined [40]. We calculated random effects models, which we deemed appropriate considering sampling differences. The Paule–Mandel estimator was chosen to measure between-study variance due to its reliability for different types of models [41]. A Q-test for heterogeneity was conducted. To quantify measures of between-study heterogeneity, we report the test statistic Q_E and corresponding p-value as well as the I² statistic. Additionally, we calculated 95% prediction intervals (PIs) for all meta-analytical models [42]. Because the “metafor::predict.rma” function unrealistically assumed that the model variance τ² was a known value [43], we instead implemented a method proposed by Higgins and colleagues that accounts for τ² being an estimate with limited precision ([44], expression 12).

Additional meta-analyses were carried out in each diagnostic category for low-risk-of-bias studies, assigned during quality assessment [35]. Subgroup analyses comparing low-risk-of-bias and moderate-risk-of-bias studies were performed through a Q-test. In cases of significant between-subgroup difference, a meta-regression model with risk of bias assessment as a single independent variable was computed to estimate the proportion of variance explained by disparities in methodological quality.

For each diagnostic category, meta-regression analyses were performed to investigate potential sources of heterogeneity. Continuous independent variables for single factor meta-regression were number of participants, sex distribution (female/all), and final year of diagnostic assessments. Categorial independent factors were diagnostic method (structured/semi-structured interview versus non-structured clinical evaluation), sampling method (randomized versus non-randomized sampling methods), and study location (US, UK, or Germany). The 3 study locations were prespecified as predictor variables due to a preponderance of primary studies in each of these countries.

Multivariable meta-regression models were also calculated. The respective independent variables were chosen through automated, information-criterion-based model selection with generalized linear models [38]. For models with 20 or more included studies, the Akaike information criterion (AIC) was used; for models with fewer than 20 included studies, we utilized the corrected version for small sample sizes (AIC_C) to avoid over-fitting.

The proportion of variance of prevalence estimates explained by any meta-regression model was estimated by the R² statistic [45].

We assumed that missingness was at random [46], so missing values in independent variables (that were missing despite requests for additional information to primary study authors) were replaced through multiple imputation by chained equations [47]. For models including incomplete predictor variables, results of meta-regression on imputed data are presented as the primary analysis; meta-regression results on only complete cases are provided as sensitivity analyses [48].

Results

Description of included studies

The systematic literature search returned 5,886 distinct records, of which 144 full texts were assessed (see S3 Table for reasons for exclusion). We identified a total of 39 studies comprising data on 8,049 homeless individuals [28,29,49–85] (see Fig 1 for flow chart of screening process). This included 10 additional studies for this update [28,29,53–55,57,59,62,75,76], and 2 previous investigations were further clarified [81,83].

Out of the 39 included studies, 27 publications reported age (mean of 41.1 years) [28,49–57,59,64,65,67,70–73,75,76,78–82,84,85], and the proportion of women was 22.3% (based on 38 studies) [28,29,49–65,67–85]. Eleven studies [52,56,68,71–74,80,82,83,85] investigated male-only samples, and 5 studies [59,65,78,81,84] solely women. Of the 39 studies, 27 were from 3 countries: 11 from the US (n = 2,694 participants) [57,59,60,64,69,75,77,79,83–85], 7 from the UK (n = 1,390 participants) [49,61,66,67,70,78,82], and 9 from Germany (n = 936 participants) [28,50,51,56,65,71–73,80,81]. Six studies were from other European countries (n = 2,301 participants) [29,52,55,58,62,76], 1 study was from Canada (n = 60 participants) [69], 2 were from Japan (n = 194 participants) [53,54], and 2 were from Australia (n = 667 participants) [63,74]. Fourteen studies reported a response rate of 85% or above [49,60,65,66,69–73,78,81,82,84,85], 20 studies reported a response rate below 85% [28,29,50–52,54–56,58,59,61–64,68,74,76,79,80,83], and 5 did not report participation rate [53,57,67,75,77]. In 13 studies, participants were accommodated in shelters, hostels, or residential care when assessed [28,49,63,66,70,72,74,76–78,81–83] while in 3 they were rough sleeping [54,62,67]; 22 studies had mixed samples regarding accommodation or provided incomplete information [29,50–53,55–61,64,65,68,69,71,73,75,79,80,84,85]. S4 Table provides further information on methodological and sample characteristics. For quality ratings, see S5 and S6 Tables. S7 Table provides all extracted data that meta-analyses and meta-regression analyses were based on.

Any current mental disorders

There were 8 surveys reporting on homeless people having at least 1 diagnosis of a current mental disorder [28,51,54,62,71–73,81], with a random effects pooled prevalence estimated at 76.2% (95% CI 64.0% to 86.6%) (Fig 2). Individual study prevalence rates ranged from 56.3% to 93.3%, with substantial heterogeneity (I² = 88% [95% CI 72% to 97%]). The 95% PI was 40% to 99%. Univariable meta-regression analysis revealed that studies with randomized sampling procedures reported significantly higher prevalence estimates than ones with other sampling procedures, accounting for a large proportion of heterogeneity (R² = 59%) (see S8 Table). Sampling procedure was chosen as the only predictor variable by multivariable model selection (see Table 1).

Fig 2 — Analytic weights are from random effects meta-analysis. Grey boxes represent study estimates; their size is proportional to the respective analytical weight. Lines through the boxes represent the 95% CIs around the study estimates. The blue diamond represents the mean estimate and its 95% CI. The vertical red dashed line indicates the mean estimate. CI, confidence interval; PI, prediction interval.

Table 1. Study-level factors associated with between-study heterogeneity in multivariable meta-regression.

Model	β (standard error) and p-value, by factor
Model	Any current mental disorder^a,b	Schizophrenia spectrum disorders	Major depression	Bipolar disorder	Alcohol use disorders^b	Drug use disorders	Personality disorders^a,b
Imputed model	—	*With R* ² *= 16%*	*With R* ² *= 32%*	*With R* ² *= 54%*	—	*With R* ² *= 42%*	—
Imputed model	—	Sample size (continuous): >−0.01 (<0.01) p = 0.04	Randomized sampling versus other: 0.17 (0.07) p = 0.03	Randomized sampling versus other: −0.11 (0.04) p = 0.03	—	Randomized sampling versus other: −0.39 (0.12) p < 0.01	—
		Sex distribution (female/all): 0.13 (0.07) p = 0.09	Sex distribution (female/all): 0.14 (0.09) p = 0.15	Sex distribution (female/all): 0.15 (0.06) p = 0.04		UK versus other locations: −0.48 (0.18) p = 0.01
		Germany versus other locations: −0.09 (0.05) p = 0.11
Complete case analysis	*With R* ² *= 59%*	*With R* ² *= 13%*	*With R* ² *= 32%*	*With R* ² *= 50%*	*With R* ² *= 27%*	*With R* ² *= 51%*	*With R* ² *= 15%*
Complete case analysis	Randomized sampling versus other: 0.23 (0.08) p = 0.03	Sample size (continuous): >−0.01 (<0.01) p = 0.07	Randomized sampling versus other: 0.18 (0.08) p = 0.03	Randomized sampling versus other: −0.12 (0.04) p = 0.03	Germany versus other locations: 0.33 (0.10) p < 0.01	Randomized sampling versus other: −0.39 (0.10) p < 0.01	North America versus other locations: 0.30 (0.17) p = 0.10
		Sex distribution (female/all): 0.14 (0.08) p = 0.08	Sex distribution (female/all): 0.18 (0.10) p = 0.10	Sex distribution (female/all): 0.12 (0.06) p = 0.09	North America versus other locations: 0.20 (0.10) p = 0.04	UK versus other locations: −0.72 (0.20) p < 0.01
		Germany versus other locations: −0.09 (0.05) p = 0.11

Open in a new tab

Statistically significant values given in bold.

^aA univariable model was chosen in model selection, so only 1 variable is presented.

^bAll variables in the multivariable model were complete, so no imputation was needed.

In a subgroup analysis of 4 low-risk-of-bias studies [62,71,73,81], the random effects prevalence was 75.3% (95% CI 50.2% to 93.6%; I² = 81% [95% CI 32% to 99%]). There was no significant difference between quality subgroups (Q = 0.03, p = 0.87).

Schizophrenia spectrum disorders

There were 35 surveys reporting on any schizophrenia spectrum disorder [28,29,49,51–58,60–74,76–78,80–85], and the random effects prevalence was 12.4% (95% CI 9.5% to 15.7%) (Fig 3), with substantial heterogeneity (I² = 93% [95% CI 89% to 96%]; 95% PI 0% to 34%). Primary investigation estimates ranged between 2.0% and 42.2%. No single model coefficient in univariable meta-regression was statistically significant. A multivariable model with sample size, proportion of female participants, and study location in Germany accounted for a small share of the heterogeneity (R² = 16%). The latter model indicated that studies with smaller samples had significantly higher prevalence rates, but only when based on imputed values (see Table 1).

Fig 3 — Analytic weights are from random effects meta-analysis. Grey boxes represent study estimates; their size is proportional to the respective analytical weight. Lines through the boxes represent the 95% CIs around the study estimates. The blue diamond represents the mean estimate and its 95% CI. The vertical red dashed line indicates the mean estimate. CI, confidence interval; PI, prediction interval; RE, random effects.

A subgroup analysis of 17 low-risk-of-bias studies [29,49,52,55,58,60,62,65,67,69,71,73,78,80,81,84,85] revealed a random effects pooled prevalence of 10.5% (95% CI 6.2% to 15.7%; I² = 94% [95% CI 88% to 98%]). The subgroup difference between low-risk-of-bias and moderate-risk-of-bias studies was non-significant, with the low-risk group resulting in a marginally lower weighted mean (Q = 1.59, p = 0.21).

Major depression

We identified 18 studies reporting prevalence estimates on major depressive disorder [28,49,52,55,57–60,62,63,65,67,71,77,80,81,84,85], with a random effects pooled prevalence of 12.6% (95% CI 7.9% to 18.2%) (Fig 4). Individual study estimates ranged between 0% and 40.6% and showed substantial heterogeneity (I² = 95% [95% CI 90% to 98%]; 95% PI 0% to 40%). Univariable meta-regression analysis produced no significant models (see S8 Table). For multivariable regression, independent variable sampling procedure and proportion of female participants were selected; the model indicated that studies with randomized sampling reported significantly higher prevalence rates (see Table 1).

Fig 4 — Analytic weights are from random effects meta-analysis. Grey boxes represent study estimates; their size is proportional to the respective analytical weight. Lines through the boxes represent the 95% CIs around the study estimates. The blue diamond represents the mean estimate and its 95% CI. The vertical red dashed line indicates the mean estimate. CI, confidence interval; PI, prediction interval; RE, random effects.

In a subgroup analysis of 13 low-risk-of-bias studies [49,52,55,58,60,62,65,67,71,80,81,84,85], the random effects pooled prevalence was 13.0% (95% CI 6.7% to 20.9%; I² = 96% [95% CI 90% to 99%]). There were no significant differences in between risk of bias subgroups (Q = 0.09, p = 0.76).

Bipolar disorder

Fourteen surveys with prevalence estimates on bipolar disorder were identified [28,49,55,57–59,62,63,65,67,71,77,84,85]. Three studies reported on solely type I bipolar disorder [49,57,85], 4 examined all bipolar disorder subtypes [28,59,65,71], and 7 did not specify [55,58,62,63,67,77,84]. The random effects pooled prevalence was 4.1% (95% CI 2.0% to 6.7%) (Fig 5), with substantial heterogeneity (I² = 89% [95% CI 77% to 96%]; 95% PI 0% to 16%). Individual estimates ranged from 1.0% to 13.5%. Univariable regression models indicated that studies with higher proportions of female participants reported significantly higher rates of bipolar disorder (see S8 Table). In the multivariable model, prevalence estimates from studies with randomized sampling were significantly lower than those from studies with other sampling methods (see Table 1).

Fig 5 — Analytic weights are from random effects meta-analysis. Grey boxes represent study estimates; their size is proportional to the respective analytical weight. Lines through the boxes represent the 95% CIs around the study estimates. The blue diamond represents the mean estimate and its 95% CI. The vertical red dashed line indicates the mean estimate. CI, confidence interval; PI, prediction interval; RE, random effects.

A subgroup analysis of 9 low-risk-of-bias surveys [49,55,58,62,65,67,71,84,85] resulted in a random effects pooled prevalence of 2.6% (95% CI 1.0% to 4.9%), with moderate heterogeneity (I² = 78% [95% CI 29% to 96%]). The difference between low-risk-of-bias and moderate-risk-of-bias studies was non-significant (Q = 2.29, p = 0.13).

Findings for any affective disorder (which included depression and bipolar disorder) are reported in S1 Text and S6 Table.

Alcohol use disorders

Estimates on alcohol use disorders could be extracted from 29 surveys [28,29,51–66,68,71–73,76,77,79–81,84,85]. The random effects pooled prevalence was 36.7% (95% CI 27.7% to 46.2%) (Fig 6), with individual study estimates ranging from 5.5% to 71.7%, and with substantial between-study heterogeneity (I² = 98% [95% CI 97% to 99%]; 95% PI 2% to 85%). Univariable meta-regression models indicated that studies with smaller samples and studies from Germany (compared to other locations) reported significantly higher rates of alcohol use disorders (see S8 Table). In multivariable analysis, the best selected model included only study location as a predictor variable, with higher prevalences reported in Germany and North America (see Table 1).

Fig 6 — Analytic weights are from random effects meta-analysis. Grey boxes represent study estimates; their size is proportional to the respective analytical weight. Lines through the boxes represent the 95% CIs around the study estimates. The blue diamond represents the mean estimate and its 95% CI. The vertical red dashed line indicates the mean estimate. CI, confidence interval; PI, prediction interval; RE, random effects.

In a subgroup analysis of 14 low-risk-of-bias studies [29,52,55,58,60,62,65,71,73,79–81,84,85], the random effects pooled prevalence was 36.9% (95% CI 21.1% to 54.3%; I² = 99% [95% CI 98% to 100%]). There was no significant difference between risk of bias subgroups (Q < 0.01, p = 0.96).

Drug use disorders

We identified 23 surveys reporting prevalence estimates on drug use disorders [28,29,52,53,55–65,71,73,76,79,80,82,84,85] (Fig 7). A random effects pooled prevalence of 21.7% (95% CI 13.1% to 31.7%) was found, with very high heterogeneity (I² = 99% [95% CI 98% to 99%]; 95% PI 0% to 74%); individual estimates ranged between 0% and 72.1%. According to univariable meta-regression, studies with randomized sampling (as opposed to other sampling methods) estimated significantly lower prevalence rates (see S8 Table). The selected multivariable model showed that studies from the UK reported lower prevalence rates. These results were confirmed by a secondary complete case analysis.

A subgroup analysis of 13 low-risk-of-bias studies [29,52,55,58,60,62,65,71,73,79,80,84,85] resulted in a random effects pooled prevalence of 18.1% (95% CI 10.5% to 27.2%), with substantial heterogeneity (I² = 97% [95% CI 94% to 99%]). The difference between subgroups was not significant (Q = 0.65, p = 0.42).

Personality disorders

Fourteen studies reported prevalence estimates on lifetime personality disorders [28,51–53,62,64,67,75–77,80,82,84,85], with a random effects pooled prevalence of 25.4% (95% CI 10.9% to 43.6%) (Fig 8). Individual estimates ranged between 0% and 98.3%, resulting in substantial heterogeneity (I² = 99% [95% CI 97% to 99%]; 95% PI 0% to 91%). Univariable regression models did not yield significant results (see S8 Table), and neither did the selected multivariable model (see Table 1).

Fig 8 — Analytic weights are from random effects meta-analysis. Grey boxes represent study estimates; their size is proportional to the respective analytical weight. Lines through the boxes represent the 95% CIs around the study estimates. The blue diamond represents the mean estimate and its 95% CI. The vertical red dashed line indicates the mean estimate. CI, confidence interval; PI, prediction interval; RE, random effects.

In a subgroup analysis of 6 low-risk-of-bias studies [52,62,67,80,84,85], the random effects pooled prevalence was 21.0% (95% CI 4.7% to 44.5%), with substantial heterogeneity (I² = 97% [95% CI 92% to 100%]). The difference between subgroups was not significant (Q = 0.32, p = 0.57).

Discussion

This systematic review and meta-analysis of the prevalence of mental illness among homeless people in high-income countries included 39 studies comprising a total of 8,049 participants. We investigated 7 common psychiatric diagnoses, and examined possible explanations for the between-study heterogeneity. We report 3 main findings.

With a pooled prevalence of around 37%, alcohol-related disorders were the most prevalent diagnostic category. This prevalence estimate is around 10-fold greater than general population estimates: An EU study reported a 12-month prevalence of 3.4% in the general population [86]. Correspondingly, drug-related disorders were the second most common current mental disorder, with a pooled prevalence of 22% (which can be compared with the 12-month prevalence in the US general population of 2.5% [87]). We found substantial variation between the individual studies contributing to these estimates, with individual study estimates ranging from 5.5% to 71.7% for alcohol-related disorders; this variation was partially accounted for by study location. Particularly, German-based samples typically had higher prevalence rates of alcohol use disorders than those from other nations. This might highlight geographical differences regarding the affordability and availability of substances, including a comparatively low alcohol tax in Germany [88]. Irrespective of this moderating factor, the strong association between homelessness and substance abuse reflects a bidirectional relationship: Alcohol and drug use represent possible coping strategies in marginalized housing situations. At the same time, substance abuse and other psychiatric disorders precede the onset of homelessness in many people, with alcohol use disorders in particular emerging at an earlier point in life compared to age-matched non-homeless comparisons [89], suggesting that substance use might contribute to the deterioration of an individual’s housing situation. Such deterioration is consistent with the links between substance use disorders and excess mortality in homeless people [11], homelessness chronicity, psychosocial problems [90], and poorer long-term housing stability [91].

A second main finding was that some study characteristics consistently explained the variations in prevalence. In 5 diagnostic groups, methods were important, specifically the number of included participants and the sampling procedure. Unexpectedly, the latter had differential effects by diagnostic group. In bipolar disorder and drug use disorders, randomization was associated with lower prevalence estimates, whereas for any current mental disorder and major depression, it was associated with higher estimates. These findings underline the importance of standardized methodological procedures for homelessness research. We recommend that new research studies should base their inclusion criteria on a standardized definition of homelessness based on ETHOS criteria [92] and use randomized sampling, standardized diagnostic instruments, and trained interviewers with clinical backgrounds (including nurses, psychologists, and medical doctors).

Our third main finding was high prevalence rates for treatable mental illnesses, with 1 in 8 homeless individuals having either major depression (12.6%) or schizophrenia spectrum disorders (12.4%). This represents a high rate of schizophrenia spectrum disorders among homeless people, and a very large excess compared to the 12-month prevalence in the general population, which for schizophrenia is estimated around 0.7% in high-income countries [86]. For major depression, the difference from the general population is not marked, as the 12-month prevalence in the US general population is estimated at 10% [93], although comparisons would need to account for the differences in age and sex structure between the samples contributing to this review and the general population. Depression remains important because it is modifiable, and because of its effects on adverse outcomes. In addition, a recent cohort study based in Vancouver, Canada, found that substance use disorders were associated with worsening of psychosis in homeless people, underscoring the links between these mental disorders, and the importance of treatment in mitigating their effects directly and indirectly [13]. This study also found elevated risks of mortality in those with psychosis and alcohol use disorders [13].

Overall, our findings underscore the importance of mental health problems among homeless individuals. This review is complemented by other research on the often precarious financial and housing situation of psychiatric patients, for whom high rates of homelessness, indebtedness, and lack of bank account ownership have been reported [94–97]. Being homeless and having mental disorders are therefore closely interrelated. Fragmented and siloed services will therefore be typically unable to address these linked psychosocial and health problems. The mental disorders reported in this study are typically associated with unmet needs in the homeless population [51,98–100], which further indicates the need for integrated approaches. Many different initiatives to address these needs have been researched over the last decade, among them Housing First, Intensive Case Management, Assertive Community Treatment, and Critical Time Intervention. Randomized controlled studies using these approaches have generally resulted in positive effects on housing stability, but only moderate or no effects on most indicators of mental health in comparison to usual care, including for substance use [101–104]. Therefore, further improvements in management and treatment are necessary that focus on these common mental disorders.

The COVID-19 pandemic has put homeless people at particular risk of infection and further marginalization [105]. But it has shown what is possible—government agencies and charity organizations managed to quickly provide accommodation to a large number of rough-sleeping homeless people in some European regions [106,107].

Some limitations to this review need to be considered. We searched a limited number of databases, so it is possible that we missed certain primary reports, although this possibility was minimized by searching through reference lists and Google Scholar citations. Furthermore, despite the high rate of multimorbidity in homeless populations [108,109], included studies lacked information on comorbidity. With most of the primary studies reporting prevalence rates of more than 1 of the investigated diagnostic categories, effects from the same sample were in many cases entered into multiple meta-analytical models. This may have led to measurement error and overestimation if diagnostic criteria overlap, but without diagnostic validity studies specific to homeless persons, this remains uncertain. We limited the number of demographic variables that we conducted heterogeneity analyses on, because of variations in measurement and reporting detail. Future work, including individual participant meta-analysis, could standardize information on age, socioeconomic background, and ethnicity, for example.

The present review focuses on high-income countries because sample and diagnostic heterogeneity would presumably increase if a wider range of countries was included. It is important to note, however, that homeless populations in low- and middle-income countries need investigation, and may have higher rates of trauma-related symptoms [110,111]. The prevalence of the mental disorders reported in the current review does not consider unmet healthcare needs or treatment provision, which are additional elements to consider in developing services. Finally, several subpopulations were underrepresented: migrants and refugees (individuals who did not speak the local language were excluded from some study samples), the “hidden homeless” population (e.g., “couch-surfers”) [112] (sampling procedures were often not able to identify this group), and, importantly, homeless women. Twenty-two percent of participants in the included studies were female, lower than most estimates of the proportion of women among homeless populations, which range between 25% and 40% [4,113].

In summary, we found high prevalence of mental disorders among homeless people in high-income countries, with around three-quarters having any mental disorder and a third having alcohol use disorders. Future research should focus on integrated service models addressing the identified needs of substance use disorders, schizophrenia spectrum disorders, and depression in homeless individuals as a priority. In addition, new work could consider focusing on underrepresented subpopulations like homeless women and migrants. Furthermore, longitudinal studies could examine mechanisms linking homelessness and mental disorders in order to develop more effective preventive measures.

Supporting information

S1 Table. Database search strings.

(DOCX)

Click here for additional data file.^{(17.3KB, docx)}

S2 Table. PRISMA 2009 checklist.

(DOCX)

Click here for additional data file.^{(24.2KB, docx)}

S3 Table. Studies excluded at full-text screening, with reasons.

(DOCX)

Click here for additional data file.^{(35.4KB, docx)}

S4 Table. Study characteristics.

(DOCX)

Click here for additional data file.^{(27.5KB, docx)}

S5 Table. JBI checklist for prevalence studies.

(DOCX)

Click here for additional data file.^{(20KB, docx)}

S6 Table. Risk of bias tool.

(DOCX)

Click here for additional data file.^{(21.8KB, docx)}

S7 Table. Data basis for meta-analyses and meta-regression analyses.

(DOCX)

Click here for additional data file.^{(30.3KB, docx)}

S8 Table. Univariable regression models.

(DOCX)

Click here for additional data file.^{(16.8KB, docx)}

S9 Table. Results of single factor meta-regression models for affective disorders (pooled).

(DOCX)

Click here for additional data file.^{(13.7KB, docx)}

S10 Table. Results of multiple factor meta-regression for affective disorders (pooled).

(DOCX)

Click here for additional data file.^{(12.9KB, docx)}

S1 Text. Affective disorders.

Results of meta-analysis and meta-regression analysis.

(DOCX)

Click here for additional data file.^{(14.1KB, docx)}

Acknowledgments

We are grateful to authors of included and non-included publications who provided additional details about their studies: C. Adams, H.-J. Salize, A. Greifenhagen, C. Vazquez, U. Beijer, C. Siegel, and G. Gilchrist. We are also grateful to the professional translator N. Spennemann for assistance with Japanese studies.

Abbreviations

CI: confidence interval
DSM: Diagnostic and Statistical Manual of Mental Disorders
PI: prediction interval

Data Availability

All relevant data are within the manuscript and its Supporting Information files.

Funding Statement

The Wellcome Trust (https://wellcome.org) granted the submission fee for this review to SF (grant number 202836/Z/16/Z). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

1.United Nations Commission for Social Development. Affordable housing and social protection systems for all to address homelessness. Report of the Secretary-General. E/CN.5/2020/3. New York: United Nations Commission for Social Development; 2019Nov27 [cited 2020 May 10]. Available from: https://undocs.org/en/E/CN.5/2020/3. [Google Scholar]
2.Directorate of Employment, Labour and Social Affairs. HC3.1 Homeless population. Paris: Organisation for Economic Co-operation and Development; 2020. [cited 2020 May 3]. Available from: https://www.oecd.org/els/family/HC3-1-Homeless-population.pdf. [Google Scholar]
3.Tsai J. Lifetime and 1-year prevalence of homelessness in the US population: results from the National Epidemiologic Survey on Alcohol and Related Conditions-III. J Public Health (Oxf). 2018;40(1):65–74. doi: 10.1093/pubmed/fdx034 [DOI] [PubMed] [Google Scholar]
4.Henry M, Mahathey A, Morrill T, Robinson A, Shivji A, Watt R. The 2018 Annual Homeless Assessment Report (AHAR) to Congress. Part 1: point-in-time estimates of homelessness. Washington (DC): US Department of Housing and Urban Development; 2018Dec [cited 2020 May 10]. Available from: https://www.huduser.gov/portal/sites/default/files/pdf/2018-AHAR-Part-1.pdf. [Google Scholar]
5.Willliams SP, Bryant K. Sexually transmitted infection prevalence among homeless adults in the United States: a systematic literature review. Sex Transm Dis. 2018;45(7):494–504. doi: 10.1097/OLQ.0000000000000780 [DOI] [PMC free article] [PubMed] [Google Scholar]
6.Topolovec-Vranic J, Ennis N, Colantonio A, Cusimano MD, Hwang SW, Kontos P, et al. Traumatic brain injury among people who are homeless: a systematic review. BMC Public Health. 2012;12(1):1059. doi: 10.1186/1471-2458-12-1059 [DOI] [PMC free article] [PubMed] [Google Scholar]
7.Nusselder WJ, Slockers MT, Krol L, Slockers CT, Looman CWN, van Beeck EF. Mortality and life expectancy in homeless men and women in Rotterdam: 2001–2010. PLoS ONE. 2013;8(10):e73979. doi: 10.1371/journal.pone.0073979 [DOI] [PMC free article] [PubMed] [Google Scholar]
8.Fazel S, Geddes JR, Kushel M. The health of homeless people in high-income countries: descriptive epidemiology, health consequences, and clinical and policy recommendations. Lancet. 2014;384(9953):1529–40. doi: 10.1016/S0140-6736(14)61132-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
9.Bernstein RS, Meurer LN, Plumb EJ, Jackson JL. Diabetes and hypertension prevalence in homeless adults in the United States: a systematic review and meta-analysis. Am J Public Health. 2014;105(2):46–60. [DOI] [PMC free article] [PubMed] [Google Scholar]
10.Beijer U, Wolf A, Fazel S. Prevalence of tuberculosis, hepatitis C virus, and HIV in homeless people: a systematic review and meta-analysis. Lancet Infect Dis. 2012;12(11):859–70. doi: 10.1016/S1473-3099(12)70177-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
11.Baggett TP, Hwang SW, O’Connell JJ, Porneala BC, Stringfellow EJ, Orav EJ, et al. Mortality among homeless adults in Boston: shifts in causes of death over a 15-year period. JAMA Intern Med. 2013;173(3):189–95. doi: 10.1001/jamainternmed.2013.1604 [DOI] [PMC free article] [PubMed] [Google Scholar]
12.Aldridge RW, Story A, Hwang SW, Nordentoft M, Luchenski SA, Hartwell G, et al. Morbidity and mortality in homeless individuals, prisoners, sex workers, and individuals with substance use disorders in high-income countries: a systematic review and meta-analysis. Lancet. 2018;391(10117):241–50. doi: 10.1016/S0140-6736(17)31869-X [DOI] [PMC free article] [PubMed] [Google Scholar]
13.Jones AA, Gicas KM, Seyedin S, Willi TS, Leonova O, Vila-Rodriguez F, et al. Associations of substance use, psychosis, and mortality among people living in precarious housing or homelessness: a longitudinal, community-based study in Vancouver, Canada. PLoS Med. 2020;17(7):e1003172. doi: 10.1371/journal.pmed.1003172 [DOI] [PMC free article] [PubMed] [Google Scholar]
14.Nielsen SF, Hjorthøj CR, Erlangsen A, Nordentoft M. Psychiatric disorders and mortality among people in homeless shelters in Denmark: a nationwide register-based cohort study. Lancet. 2011;377(9784):2205–14. doi: 10.1016/S0140-6736(11)60747-2 [DOI] [PubMed] [Google Scholar]
15.Perron BE, Alexander-Eitzman B, Gillespie DF, Pollio D. Modeling the mental health effects of victimization among homeless persons. Soc Sci Med. 2008;67(9):1475–9. doi: 10.1016/j.socscimed.2008.07.012 [DOI] [PMC free article] [PubMed] [Google Scholar]
16.Roy L, Crocker AG, Nicholls TL, Latimer EA, Ayllon AR. Criminal behavior and victimization among homeless individuals with severe mental illness: a systematic review. Psychiatr Serv. 2014;65(6):739–50. doi: 10.1176/appi.ps.201200515 [DOI] [PubMed] [Google Scholar]
17.Caton CLM, Dominguez B, Schanzer B, Hasin DS, Shrout PE, Felix A, et al. Risk factors for long-term homelessness: findings from a longitudinal study of first-time homeless single adults. Am J Public Health. 2005;95(10):1753–9. doi: 10.2105/AJPH.2005.063321 [DOI] [PMC free article] [PubMed] [Google Scholar]
18.Patterson ML, Somers JM, Moniruzzaman A. Prolonged and persistent homelessness: multivariable analyses in a cohort experiencing current homelessness and mental illness in Vancouver, British Columbia. Ment Health Subst Use. 2012;5(2):85–101. [Google Scholar]
19.Skosireva A, O’Campo P, Zerger S, Chambers C, Gapka S, Stergiopoulos V. Different faces of discrimination: perceived discrimination among homeless adults with mental illness in healthcare settings. BMC Health Serv Res. 2014;14(1):376. doi: 10.1186/1472-6963-14-376 [DOI] [PMC free article] [PubMed] [Google Scholar]
20.Hossain MM, Sultana A, Tasnim S, Fan Q, Ma P, McKyer ELJ, et al. Prevalence of mental disorders among people who are homeless: an umbrella review. Int J Soc Psychiatry. 2020;66(6):528–41. doi: 10.1177/0020764020924689 [DOI] [PubMed] [Google Scholar]
21.Ayano G, Tesfaw G, Shumet S. The prevalence of schizophrenia and other psychotic disorders among homeless people: a systematic review and meta-analysis. BMC Psychiatry. 2019;19(1):370. doi: 10.1186/s12888-019-2361-7 [DOI] [PMC free article] [PubMed] [Google Scholar]
22.Ayano G, Tsegay L, Abraha M, Yohannes K. Suicidal ideation and attempt among homeless people: a systematic review and meta-analysis. Psychiatr Q. 2019;90(4):829–42. doi: 10.1007/s11126-019-09667-8 [DOI] [PubMed] [Google Scholar]
23.Depp CA, Vella L, Orff HJ, Twamley EW. A quantitative review of cognitive functioning in homeless adults. J Nerv Ment Dis. 2015;203(2):126–31. doi: 10.1097/NMD.0000000000000248 [DOI] [PMC free article] [PubMed] [Google Scholar]
24.Embleton L, Mwangi A, Vreeman R, Ayuku D, Braitstein P. The epidemiology of substance use among street children in resource‐constrained settings: a systematic review and meta‐analysis. Addiction. 2013;108(10):1722–33. doi: 10.1111/add.12252 [DOI] [PMC free article] [PubMed] [Google Scholar]
25.Bassuk EL, Richard MK, Tsertsvadze A. The prevalence of mental illness in homeless children: a systematic review and meta-analysis. J Am Acad Child Adolesc Psychiatry. 2015;54(2):86–96. doi: 10.1016/j.jaac.2014.11.008 [DOI] [PubMed] [Google Scholar]
26.Schreiter S, Bermpohl F, Krausz M, Leucht S, Rössler W, Schouler-Ocak M, et al. The prevalence of mental illness in homeless people in Germany. Dtsch Arztebl Int. 2017;114(40):665–72. doi: 10.3238/arztebl.2017.0665 [DOI] [PMC free article] [PubMed] [Google Scholar]
27.Fazel S, Khosla V, Doll H, Geddes J. The prevalence of mental disorders among the homeless in western countries: systematic review and meta-regression analysis. PLoS Med. 2008;5(12):e225. doi: 10.1371/journal.pmed.0050225 [DOI] [PMC free article] [PubMed] [Google Scholar]
28.Bäuml J, Brönner M, Baur B, Pitschel-Walz GG, Jahn T, Bäuml J. Die SEEWOLF-Studie: seelische Erkrankungsrate in den Einrichtungen der Wohnungslosenhilfe im Großraum München. Archiv für Wissenschaft und Praxis der sozialen Arbeit. Freiburg im Breisgau: Lambertus-Verlag; 2017. [Google Scholar]
29.Laporte A, Vandentorren S, Detrez M-A, Douay C, Le Strat Y, Le Mener E, et al. Prevalence of mental disorders and addictions among homeless people in the greater Paris area, France. Int J Environ Res Public Health. 2018;15(2):241. doi: 10.3390/ijerph15020241 [DOI] [PMC free article] [PubMed] [Google Scholar]
30.Williams JBW. The multiaxial system of DSM-III: where did it come from and where should it go?: II. Empirical studies, innovations, and recommendations. Arch Gen Psychiatry. 1985;42(2):181–6. doi: 10.1001/archpsyc.1985.01790250075010 [DOI] [PubMed] [Google Scholar]
31.Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA. 2000;283(15):2008–12. doi: 10.1001/jama.283.15.2008 [DOI] [PubMed] [Google Scholar]
32.Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med. 2009;6(7):e1000097. doi: 10.1371/journal.pmed.1000097 [DOI] [PMC free article] [PubMed] [Google Scholar]
33.World Bank. World Bank country and lending groups. Washington (DC): World Bank; 2020. [cited 2020 Sep 11]. Available from: https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country-and-lending-groups. [Google Scholar]
34.JBI. Critical appraisal tools. Adelaide: University of Adelaide; 2021 [cited 2021 Aug 12]. Available from: https://jbi.global/critical-appraisal-tools.
35.Hoy D, Brooks P, Woolf A, Blyth F, March L, Bain C, et al. Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement. J Clin Epidemiol. 2012;65(9):934–9. doi: 10.1016/j.jclinepi.2011.11.014 [DOI] [PubMed] [Google Scholar]
36.Bates D, Chambers J, Dalgaard P, Gentleman R, Hornik K, Ihaka R, et al. R-4.0.4. Comprehensive R Archive Network; 2021. [cited 2021 Apr 21]. Available from: https://cran.r-project.org/. [Google Scholar]
37.Van Buuren S, Groothuis-Oudshoorn K. mice: multivariate imputation by chained equations in R. J Stat Softw. 2011Dec12. doi: 10.18637/jss.v045.i03 [DOI] [Google Scholar]
38.Calcagno V, de Mazancourt C. glmulti: an R package for easy automated model selection with (generalized) linear models. J Stat Softw. 2010May31. doi: 10.18637/jss.v034.i12 [DOI] [Google Scholar]
39.Viechtbauer W. Conducting meta-analyses in R with the metafor package. J Stat Softw. 2010Aug5. doi: 10.18637/jss.v036.i03 [DOI] [Google Scholar]
40.Barendregt JJ, Doi SA, Lee YY, Norman RE, Vos T. Meta-analysis of prevalence. J Epidemiol Community Health. 2013;67(11):974–8. doi: 10.1136/jech-2013-203104 [DOI] [PubMed] [Google Scholar]
41.Veroniki AA, Jackson D, Viechtbauer W, Bender R, Bowden J, Knapp G, et al. Methods to estimate the between-study variance and its uncertainty in meta-analysis. Res Synth Methods. 2016;7(1):55–79. doi: 10.1002/jrsm.1164 [DOI] [PMC free article] [PubMed] [Google Scholar]
42.Riley RD, Higgins JPT, Deeks JJ. Interpretation of random effects meta-analyses. BMJ. 2011;342:964–7. doi: 10.1136/bmj.d549 [DOI] [PubMed] [Google Scholar]
43.Viechtbauer W. Package ‘metafor.’ Version 2.4–0. Comprehensive R Archive Network; 2020 [cited 2021 Apr 21]. Available from: https://cran.r-project.org/web/packages/metafor/metafor.pdf.
44.Higgins JPT, Thompson SG, Spiegelhalter DJ. A re-evaluation of random-effects meta-analysis. J R Stat Soc Ser A Stat Soc. 2009;172(1):137–59. doi: 10.1111/j.1467-985X.2008.00552.x [DOI] [PMC free article] [PubMed] [Google Scholar]
45.Anderson-Sprecher R. Model comparisons and R^2. Am Stat. 1994;48(2):113–7. [Google Scholar]
46.Little RJ, D’Agostino R, Cohen ML, Dickersin K, Emerson SS, Farrar JT, et al. The prevention and treatment of missing data in clinical trials. N Engl J Med. 2012;367(14):1355–60. doi: 10.1056/NEJMsr1203730 [DOI] [PMC free article] [PubMed] [Google Scholar]
47.Azur MJ, Stuart EA, Frangakis C, Leaf PJ. Multiple imputation by chained equations: what is it and how does it work? Int J Methods Psychiatr Res. 2011;20(1):40–9. doi: 10.1002/mpr.329 [DOI] [PMC free article] [PubMed] [Google Scholar]
48.Jakobsen JC, Gluud C, Wetterslev J, Winkel P. When and how should multiple imputation be used for handling missing data in randomised clinical trials—a practical guide with flowcharts. BMC Med Res Methodol. 2017;17(1):162. doi: 10.1186/s12874-017-0442-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
49.Sclare PD. Psychiatric disorder among the homeless in Aberdeen. Scott Med J. 1997;42(6):173–7. doi: 10.1177/003693309704200605 [DOI] [PubMed] [Google Scholar]
50.Salize HJ, Dillmann-Lange C, Stern G, Kentner-Figura B, Stamm K, Rossler W, et al. Alcoholism and somatic comorbidity among homeless people in Mannheim, Germany. Addiction. 2002;97(12):1593–600. doi: 10.1046/j.1360-0443.2002.00235.x [DOI] [PubMed] [Google Scholar]
51.Salize HJ, Horst A, Dillmann-Lange C, Killmann U, Stern G, Wolf I, et al. Needs for mental health care and service provision in single homeless people. Soc Psychiatry Psychiatr Epidemiol. 2001;36(4):207–16. doi: 10.1007/s001270170065 [DOI] [PubMed] [Google Scholar]
52.Reinking DP, Wolf JR, Kroon H. Hoge prevalentie van psychische stoornissen en verslavingsproblemen bij daklozen in de stad Utrecht. Ned Tijdschr Geneeskd. 2001;145(24):1161–6. [PubMed] [Google Scholar]
53.Nishio A, Yamamoto M, Horita R, Sado T, Ueki H, Watanabe T, et al. Prevalence of mental illness, cognitive disability, and their overlap among the homeless in Nagoya, Japan. PLoS ONE. 2015;10(9):e0138052. doi: 10.1371/journal.pone.0138052 [DOI] [PMC free article] [PubMed] [Google Scholar]
54.Morikawa S, Uehara R, Okuda K, Shimizu H, Nakamura Y. [Prevalence of psychiatric disorders among homeless people in one area of Tokyo.] Nihon Koshu Eisei Zasshi. 2011;58(5):331–9. [PubMed] [Google Scholar]
55.Madianos MG, Chondraki P, Papadimitriou GN. Prevalence of psychiatric disorders among homeless people in Athens area: a cross-sectional study. Soc Psychiatry Psychiatr Epidemiol. 2013;48(8):1225–34. doi: 10.1007/s00127-013-0674-2 [DOI] [PubMed] [Google Scholar]
56.Längle G, Egerter B, Albrecht F, Petrasch M, Buchkremer G. Prevalence of mental illness among homeless men in the community. Soc Psychiatry Psychiatr Epidemiol. 2005;40(5):382–90. doi: 10.1007/s00127-005-0902-5 [DOI] [PubMed] [Google Scholar]
57.Krausz RM, Clarkson AF, Strehlau V, Torchalla I, Li K, Schuetz CG. Mental disorder, service use, and barriers to care among 500 homeless people in 3 different urban settings. Soc Psychiatry Psychiatr Epidemiol. 2013;48(8):1235–43. doi: 10.1007/s00127-012-0649-8 [DOI] [PubMed] [Google Scholar]
58.Kovess V, Mangin Lazarus C. The prevalence of psychiatric disorders and use of care by homeless people in Paris. Soc Psychiatry Psychiatr Epidemiol. 1999;34(11):580–7. doi: 10.1007/s001270050178 [DOI] [PubMed] [Google Scholar]
59.Whitbeck LB, Armenta BE, Welch-Lazoritz ML. Borderline personality disorder and Axis I psychiatric and substance use disorders among women experiencing homelessness in three US cities. Soc Psychiatry Psychiatr Epidemiol. 2015;50(8):1285–91. doi: 10.1007/s00127-015-1026-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
60.Koegel P, Burnam MA, Farr RK. The prevalence of specific psychiatric disorders among homeless individuals in the inner city of Los Angeles. Arch Gen Psychiatry. 1988;45(12):1085–92. doi: 10.1001/archpsyc.1988.01800360033005 [DOI] [PubMed] [Google Scholar]
61.Kershaw A, Singleton N, Meltzer H. Survey of the health and well-being of homeless people in Glasgow. Int Rev Psychiatry. 2003;15(1–2):141–3. doi: 10.1080/0954026021000046065 [DOI] [PubMed] [Google Scholar]
62.Hynes F, Kilbride K, Fenton J. A survey of mental disorder in the long-term, rough sleeping, homeless population of inner Dublin. Ir J Psychol Med. 2019;36(1):19–22. doi: 10.1017/ipm.2018.23 [DOI] [PubMed] [Google Scholar]
63.Herrman H, McGorry P, Bennett P, van Riel R, Singh B. Prevalence of severe mental disorders in disaffiliated and homeless people in inner Melbourne. Am J Psychiatry. 1989;146(9):1179–84. doi: 10.1176/ajp.146.9.1179 [DOI] [PubMed] [Google Scholar]
64.Haugland G, Siegel C, Hopper K, Alexander MJ. Mental illness among homeless individuals in a suburban county. Psychiatr Serv. 1997;48(4):504–9. doi: 10.1176/ps.48.4.504 [DOI] [PubMed] [Google Scholar]
65.Greifenhagen A, Fichter M. Mental illness in homeless women: an epidemiological study in Munich, Germany. Eur Arch Psychiatry Clin Neurosci. 1997;247(3):162–72. doi: 10.1007/BF03033070 [DOI] [PubMed] [Google Scholar]
66.Gill B, Meltzer H, Hinds K. The prevalence of psychiatric morbidity among homeless adults. Int Rev Psychiatry. 2003;15(1–2):134–40. doi: 10.1080/0954026021000046056 [DOI] [PubMed] [Google Scholar]
67.Geddes J, Newton R, Young G, Bailey S, Freeman C, Priest R. Comparison of prevalence of schizophrenia among residents of hostels for homeless people in 1966 and 1992. BMJ. 1994;308(6932):816–9. doi: 10.1136/bmj.308.6932.816 [DOI] [PMC free article] [PubMed] [Google Scholar]
68.Freeman SJ, Formo A, Alampur AG, Sommers AF. Psychiatric disorder in a skid-row mission population. Compr Psychiatry. 1979;20(5):454–62. doi: 10.1016/0010-440x(79)90031-2 [DOI] [PubMed] [Google Scholar]
69.Fischer PJ, Shapiro S, Breakey WR, Anthony JC, Kramer M. Mental health and social characteristics of the homeless: a survey of mission users. Am J Public Health. 1986;76(5):519–24. doi: 10.2105/ajph.76.5.519 [DOI] [PMC free article] [PubMed] [Google Scholar]
70.Weller BG, Weller MP, Coker E, Mahomed S. Crisis at Christmas 1986. Lancet. 1987;1(8532):553–4. doi: 10.1016/s0140-6736(87)90187-5 [DOI] [PubMed] [Google Scholar]
71.Fichter MM, Quadflieg N. Prevalence of mental illness in homeless men in Munich, Germany: results from a representative sample. Acta Psychiatr Scand. 2001;103(2):94–104. doi: 10.1034/j.1600-0447.2001.00217.x [DOI] [PubMed] [Google Scholar]
72.Eikelmann B, Inhester ML, Reker T. Psychische Störungen bei nichtsesshaften Männern. Defizite in der psychiatrischen Versorgung. Sozialpsychiatr Informationen. 1992;29–32. [Google Scholar]
73.Dufeu P, Podschus J, Schmidt LG. Alkoholabhängigkeit bei männlichen Wohnungslosen. Häufigkeit, Ausprägung und Determinanten. Nervenarzt. 1996;67(11):930–4. [DOI] [PubMed] [Google Scholar]
74.Doutney CP, Buhrich N, Virgona A, Cohen A, Daniels P. The prevalence of schizophrenia in a refuge for homeless men. Aust N Z J Psychiatry. 1985;19(3):233–8. doi: 10.3109/00048678509158828 [DOI] [PubMed] [Google Scholar]
75.Conolly AJ, Cobb-Richardson P, Ball SA. Personality disorders in homeless drop-in centre clients. J Pers Disord. 2008;22(6):573–88. doi: 10.1521/pedi.2008.22.6.573 [DOI] [PubMed] [Google Scholar]
76.Briner D, Jäger M, Kawohl W, Baumgartner-Nietlisbach G. Mental disorder and self-rated health among homeless people in Zurich: first epidemiological data from Switzerland. Psychiatr Prax. 2017;44(6):339–47. doi: 10.1055/s-0042-111742 [DOI] [PubMed] [Google Scholar]
77.Bassuk EL, Rubin L, Lauriat A. Is homelessness a mental health problem? Am J Psychiatry. 1984;141(12):1546–50. doi: 10.1176/ajp.141.12.1546 [DOI] [PubMed] [Google Scholar]
78.Adams CE, Pantelis C, Duke PJ, Barnes TRE. Psychopathology, social and cognitive functioning in a hostel for homeless women. Br J Psychiatry. 1996;168(1):82–6. doi: 10.1192/bjp.168.1.82 [DOI] [PubMed] [Google Scholar]
79.North CS, Eyrich-Garg KM, Pollio DE, Thirthalli J. A prospective study of substance use and housing stability in a homeless population. Soc Psychiatry Psychiatr Epidemiol. 2009;45(11):1055–62. doi: 10.1007/s00127-009-0144-z [DOI] [PubMed] [Google Scholar]
80.Völlm B, Becker H, Kunstmann W. Psychiatrische Morbidität bei allein stehenden wohnungslosen Männern. Psychiatr Prax. 2004;31(5):236–40. doi: 10.1055/s-2003-815014 [DOI] [PubMed] [Google Scholar]
81.Torchalla I, Albrecht F, Buchkremer G, Längle G. Wohnungslose Frauen mit psychischer Erkrankung—eine Feldstudie. Psychiatr Prax. 2004;31(05):228–35. [DOI] [PubMed] [Google Scholar]
82.Timms PW, Fry AH. Homelessness and mental illness. Health Trends. 1989;21(3):70–1. [PubMed] [Google Scholar]
83.Susser E, Struening EL, Conover S. Psychiatric problems in homeless men. Lifetime psychosis, substance use, and current distress in new arrivals at New York City shelters. Arch Gen Psychiatry. 1989;46(9):845–50. doi: 10.1001/archpsyc.1989.01810090087012 [DOI] [PubMed] [Google Scholar]
84.Smith EM, North CS, Spitznagel EL. Alcohol, drugs, and psychiatric comorbidity among homeless women: an epidemiologic study. J Clin Psychiatry. 1993;54(3):82–7. [PubMed] [Google Scholar]
85.Smith EM, North CS, Spitznagel EL. A systematic study of mental illness, substance abuse, and treatment in 600 homeless men. Ann Clin Psychiatry. 1992;4(2):111–20. [Google Scholar]
86.Wittchen H-U, Jacobi F. Size and burden of mental disorders in Europe—a critical review and appraisal of 27 studies. Eur Neuropsychopharmacol. 2005;15(4):357–76. doi: 10.1016/j.euroneuro.2005.04.012 [DOI] [PubMed] [Google Scholar]
87.Merikangas KR, McClair VL. Epidemiology of substance use disorders. Hum Genet. 2012;131(6):779–89. doi: 10.1007/s00439-012-1168-0 [DOI] [PMC free article] [PubMed] [Google Scholar]
88.Adams M, Effertz T. Effective prevention against risky underage drinking—the need for higher excise taxes on alcoholic beverages in Germany. Alcohol Alcohol. 2010;45(4):387–94. doi: 10.1093/alcalc/agq031 [DOI] [PubMed] [Google Scholar]
89.North CS, Pollio DE, Smith EM, Spitznagel EL. Correlates of early onset and chronicity of homelessness in a large urban homeless population. J Nerv Ment Dis. 1998;186(7):393–400. doi: 10.1097/00005053-199807000-00002 [DOI] [PubMed] [Google Scholar]
90.Stein JA, Dixon EL, Nyamathi AM. Effects of psychosocial and situational variables on substance abuse among homeless adults. Psychol Addict Behav. 2008;22(3):410–6. doi: 10.1037/0893-164X.22.3.410 [DOI] [PMC free article] [PubMed] [Google Scholar]
91.Aubry T, Duhoux A, Klodawsky F, Ecker J, Hay E. A longitudinal study of predictors of housing stability, housing quality, and mental health functioning among single homeless individuals staying in emergency shelters. Am J Community Psychol. 2016;58(1–2):123–35. doi: 10.1002/ajcp.12067 [DOI] [PubMed] [Google Scholar]
92.Amore K, Baker M, Howden-Chapman P. The ETHOS definition and classification of homelessness: an analysis. Eur J Homelessness. 2011;5(2):19–37. [Google Scholar]
93.Hasin DS, Sarvet AL, Meyers JL, Saha TD, Ruan WJ, Stohl M, et al. Epidemiology of adult DSM-5 major depressive disorder and its specifiers in the United States. JAMA Psychiatry. 2018;75(4):336–46. doi: 10.1001/jamapsychiatry.2017.4602 [DOI] [PMC free article] [PubMed] [Google Scholar]
94.Schreiter S, Bermpohl F, Schouler-Ocak M, Krausz R, Rössler W, Heinz A, et al. Bank account ownership and access among in-patients in psychiatric care in Berlin, Germany—a cross-sectional patient survey. Front Psychiatry. 2020;11:508. doi: 10.3389/fpsyt.2020.00508 [DOI] [PMC free article] [PubMed] [Google Scholar]
95.Schreiter S, Fritz FD, Rössler W, Majić T, Schouler-Ocak M, Krausz MR, et al. [Housing Situation Among People with Substance Use Disorder in a Psychiatric Centre in Berlin, Germany—A Cross-Sectional Patient Survey.] Psychiatr Prax. 2021;48:156–60. doi: 10.1055/a-1290-5091 [DOI] [PubMed] [Google Scholar]
96.Schreiter S, Heidrich S, Heinz A, Rössler W, Krausz RM, Schouler-Ocak M, et al. [Debts, loans and unpaid bills among day patients and inpatients in psychiatric care in Berlin, Germany.] Nervenarzt. 2020Oct14. doi: 10.1007/s00115-020-01013-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
97.Schreiter S, Heidrich S, Zulauf J, Saathoff U, Brückner A, Majic T, et al. Housing situation and healthcare for patients in a psychiatric centre in Berlin, Germany: a cross-sectional patient survey. BMJ Open. 2019;9(12):e032576. doi: 10.1136/bmjopen-2019-032576 [DOI] [PMC free article] [PubMed] [Google Scholar]
98.Currie LB, Patterson ML, Moniruzzaman A, McCandless LC, Somers JM. Examining the relationship between health-related need and the receipt of care by participants experiencing homelessness and mental illness. BMC Health Serv Res. 2014;14:404. doi: 10.1186/1472-6963-14-404 [DOI] [PMC free article] [PubMed] [Google Scholar]
99.Desai MM, Rosenheck RA. Unmet need for medical care among homeless adults with serious mental illness. Gen Hosp Psychiatry. 2005;27(6):418–25. doi: 10.1016/j.genhosppsych.2005.06.003 [DOI] [PubMed] [Google Scholar]
100.Chondraki P, Madianos MG, Dragioti E, Papadimitriou GN. Homeless mentally ill in Athens area: a cross-sectional study on unmet needs and help-seeking. Int J Soc Psychiatry. 2013;60(6):544–53. doi: 10.1177/0020764013503150 [DOI] [PubMed] [Google Scholar]
101.Clarke GN, Herinckx HA, Kinney RF, Paulson RI, Cutler DL, Lewis K, et al. Psychiatric hospitalizations, arrests, emergency room visits, and homelessness of clients with serious and persistent mental illness: findings from a randomized trial of two ACT programs vs. usual care. Ment Health Serv Res. 2000;2(3):155–64. doi: 10.1023/a:1010141826867 [DOI] [PubMed] [Google Scholar]
102.Stergiopoulos V, Hwang SW, Gozdzik A, Nisenbaum R, Latimer E, Rabouin D, et al. Effect of scattered-site housing using rent supplements and intensive case management on housing stability among homeless adults with mental illness: a randomized trial. JAMA. 2015;313(9):905–15. doi: 10.1001/jama.2015.1163 [DOI] [PubMed] [Google Scholar]
103.Rosenheck R, Kasprow W, Frisman L, Liu-Mares W. Cost-effectiveness of supported housing for homeless persons with mental illness. Arch Gen Psychiatry. 2003;60(9):940–51. doi: 10.1001/archpsyc.60.9.940 [DOI] [PubMed] [Google Scholar]
104.Herman D, Opler L, Felix A, Valencia E, Wyatt RJ, Susser E. A critical time intervention with mentally iII homeless men: Impact on psychiatric symptoms. J Nerv Ment Dis. 2000;188(3):135–40. doi: 10.1097/00005053-200003000-00002 [DOI] [PubMed] [Google Scholar]
105.Perri M, Dosani N, Hwang SW. COVID-19 and people experiencing homelessness: challenges and mitigation strategies. CMAJ. 2020;192(26):e716–9. doi: 10.1503/cmaj.200834 [DOI] [PMC free article] [PubMed] [Google Scholar]
106.Ministry of Housing, Communities & Local Government, Jenrick R. 6,000 new supported homes as part of landmark commitment to end rough sleeping. London: Ministry of Housing, Communities & Local Government; 2020May24 [cited 2021 Jan 1]. Available from: https://www.gov.uk/government/news/6-000-new-supported-homes-as-part-of-landmark-commitment-to-end-rough-sleeping. [Google Scholar]
107.Deutsche Welle. Berlin opens first hostel for the homeless amid coronavirus pandemic. Deutsche Welle. 2020 Mar 31 [cited 2021 Jan 2]. Available from: https://www.dw.com/en/berlin-opens-first-hostel-for-the-homeless-amid-coronavirus-pandemic/a-52972263.
108.Bowen M, Marwick S, Marshall T, Saunders K, Burwood S, Yahyouche A, et al. Multimorbidity and emergency department visits by a homeless population: a database study in specialist general practice. Br J Gen Pract. 2019;69(685):e515–25. doi: 10.3399/bjgp19X704609 [DOI] [PMC free article] [PubMed] [Google Scholar]
109.Raphael R-W, Caroline S, Dan L, Megan A, Briony H. Premature frailty, geriatric conditions and multimorbidity among people experiencing homelessness: a cross-sectional observational study in a London hostel. Housing Care Support. 2020;23(3–4):77–91. [Google Scholar]
110.Abdu L, Withers J, Habib AG, Mijinyawa MS, Yusef SM. Disease pattern and social needs of street people in the race course area of Kano, Nigeria. J Health Care Poor Underserved. 2013;24(1):97–105. doi: 10.1353/hpu.2013.0010 [DOI] [PubMed] [Google Scholar]
111.Mathebula SD, Ross E. Realizing or relinquishing rights? Homeless youth, their life on the streets and their knowledge and experience of health and social services in Hillbrow, South Africa. Soc Work Health Care. 2013;52(5):449–66. doi: 10.1080/00981389.2012.742483 [DOI] [PubMed] [Google Scholar]
112.Agans RP, Jefferson MT, Bowling JM, Zeng D, Yang J, Silverbush M. Enumerating the hidden homeless: Strategies to estimate the homeless gone missing from a point-in-time count. J Off Stat. 2014;30(2):215–29. [Google Scholar]
113.Neupert P. Statistikbericht 2017. Berlin: Bundesarbeitsgemeinschaft Wohnungslosenhilfe. 2018. [cited 2020 Jul 18]. Available from: https://www.bagw.de/fileadmin/bagw/media/Doc/STA/STA_Statistikbericht_2017.pdf. [Google Scholar]

PLoS Med. doi: 10.1371/journal.pmed.1003750.r001

Decision Letter 0

Caitlin Moyer

3 Feb 2021

Dear Dr Fazel,

Thank you for submitting your manuscript entitled "The prevalence of mental disorders among homeless people in high-income

countries: updated systematic review and meta-regression analysis" for consideration by PLOS Medicine.

Your manuscript has now been evaluated by the PLOS Medicine editorial staff as well as by an academic editor with relevant expertise and I am writing to let you know that we would like to send your submission out for external peer review.

However, before we can send your manuscript to reviewers, we need you to complete your submission by providing the metadata that is required for full assessment. To this end, please login to Editorial Manager where you will find the paper in the 'Submissions Needing Revisions' folder on your homepage. Please click 'Revise Submission' from the Action Links and complete all additional questions in the submission questionnaire.

Please re-submit your manuscript within two working days, i.e. by .

Once your full submission is complete, your paper will undergo a series of checks in preparation for peer review. Once your manuscript has passed all checks it will be sent out for review.

Feel free to email us at plosmedicine@plos.org if you have any queries relating to your submission.

Kind regards,

Caitlin Moyer, Ph.D.

Associate Editor

PLOS Medicine

PLoS Med. doi: 10.1371/journal.pmed.1003750.r002

Decision Letter 1

Caitlin Moyer

18 Mar 2021

Dear Dr. Fazel,

Thank you very much for submitting your manuscript "The prevalence of mental disorders among homeless people in high-income countries: updated systematic review and meta-regression analysis" (PMEDICINE-D-21-00563R1) for consideration at PLOS Medicine.

Your paper was evaluated by a senior editor and discussed among all the editors here. It was also sent to four independent reviewers, including a statistical reviewer. The reviews are appended at the bottom of this email and any accompanying reviewer attachments can be seen via the link below:

[LINK]

In light of these reviews, I am afraid that we will not be able to accept the manuscript for publication in the journal in its current form, but we would like to consider a revised version that addresses the reviewers' and editors' comments. Obviously we cannot make any decision about publication until we have seen the revised manuscript and your response, and we plan to seek re-review by one or more of the reviewers.

In revising the manuscript for further consideration, your revisions should address the specific points made by each reviewer and the editors. Please also check the guidelines for revised papers at http://journals.plos.org/plosmedicine/s/revising-your-manuscript for any that apply to your paper. In your rebuttal letter you should indicate your response to the reviewers' and editors' comments, the changes you have made in the manuscript, and include either an excerpt of the revised text or the location (eg: page and line number) where each change can be found. Please submit a clean version of the paper as the main article file; a version with changes marked should be uploaded as a marked up manuscript.

In addition, we request that you upload any figures associated with your paper as individual TIF or EPS files with 300dpi resolution at resubmission; please read our figure guidelines for more information on our requirements: http://journals.plos.org/plosmedicine/s/figures. While revising your submission, please upload your figure files to the PACE digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at PLOSMedicine@plos.org.

We expect to receive your revised manuscript by Apr 08 2021 11:59PM. Please email us (plosmedicine@plos.org) if you have any questions or concerns.

***Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.***

We ask every co-author listed on the manuscript to fill in a contributing author statement, making sure to declare all competing interests. If any of the co-authors have not filled in the statement, we will remind them to do so when the paper is revised. If all statements are not completed in a timely fashion this could hold up the re-review process. If new competing interests are declared later in the revision process, this may also hold up the submission. Should there be a problem getting one of your co-authors to fill in a statement we will be in contact. YOU MUST NOT ADD OR REMOVE AUTHORS UNLESS YOU HAVE ALERTED THE EDITOR HANDLING THE MANUSCRIPT TO THE CHANGE AND THEY SPECIFICALLY HAVE AGREED TO IT. You can see our competing interests policy here: http://journals.plos.org/plosmedicine/s/competing-interests.

Please use the following link to submit the revised manuscript:

https://www.editorialmanager.com/pmedicine/

Your article can be found in the "Submissions Needing Revision" folder.

To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. Additionally, PLOS ONE offers an option to publish peer-reviewed clinical study protocols. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols

Please ensure that the paper adheres to the PLOS Data Availability Policy (see http://journals.plos.org/plosmedicine/s/data-availability), which requires that all data underlying the study's findings be provided in a repository or as Supporting Information. For data residing with a third party, authors are required to provide instructions with contact information for obtaining the data. PLOS journals do not allow statements supported by "data not shown" or "unpublished results." For such statements, authors must provide supporting data or cite public sources that include it.

We look forward to receiving your revised manuscript.

Sincerely,

Caitlin Moyer, Ph.D.

Associate Editor

PLOS Medicine

plosmedicine.org

-----------------------------------------------------------

Requests from the editors:

1. Abstract: Please report your abstract according to PRISMA for abstracts, following the PLOS Medicine abstract structure (Background, Methods and Findings, Conclusions) http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001419 .

2. Abstract Background: Provide the context of why the study is important. The final sentence should clearly state the study question.

3. Abstract: Methods and Findings: Please provide the dates of search, data sources, types of study designs included, eligibility criteria, and synthesis/appraisal methods.

4. Abstract: Methods and Findings: Please conclude this section with a sentence describing the main limitation(s) of the study.

5. Abstract: Please include the study registration number in the Abstract.

6. Author Summary: At this stage, we ask that you include a short, non-technical Author Summary of your research to make findings accessible to a wide audience that includes both scientists and non-scientists. The Author Summary should immediately follow the Abstract in your revised manuscript. This text is subject to editorial change and should be distinct from the scientific abstract. Please see our author guidelines for more information: https://journals.plos.org/plosmedicine/s/revising-your-manuscript#loc-author-summary

7. Introduction: Please expand on the rationale for the study: address past research and explain the need for and potential importance of the study.

8. Methods: Search Strategy: Please update the search to the present time (the end date is noted as October 2019).

9. Methods: Please describe how you evaluated risk of bias, including publication bias.

10. Results: Line 191: If 5 of the studies did not report a participation rate, please clarify how was it determined whether the participation rate was 50% or greater (as outlined in the exclusion criteria)?

11. Results: Line 256: Please clarify if “preferences” should be “prevalence” here.

12. References: Please check formatting of references. Please us the "Vancouver" style for reference formatting, and see our website for other reference guidelines https://journals.plos.org/plosmedicine/s/submission-guidelines#loc-references

In Ref 24, Jama should be JAMA, for example.

13. Figure 1: It may be helpful to indicate at least broadly indicate reasons for exclusion in the flow diagram at screening points.

14. Figures 2-8. For each figure, please provide a descriptive legend describing what is shown in the figure (for example, including the data points and bars, dotted line).

15. PRISMA Checklist: Thank you for including the checklist as a supporting information file. Please revise the checklist, using section and paragraph numbers to refer to locations within the text, as opposed to page numbers.

16. S3 Table: Please define all abbreviations in a legend for the Table.

17. S4 and S5 Tables: It would be helpful to include more descriptive title/legends for these tables.

18. S1 Text: Can you please explain why the results for affective disorders are being reported separately from the main text?

Comments from the reviewers:

Reviewer #1: See attachment

Michael Dewey

Reviewer #2: This manuscripts introduced a well conducted meta analysis and literature review study that aims to investigate the prevalence of mental disorders among homeless population in selected countries. The study is well conducted in that it used creditable guidelines and went through a solid process to retrieve fitting articles. It then used well recognized statistical method in data analysis. The writing of the paper in each section is clear. Discussion has its focus. The whole manuscript in writing and presenting key components of the study is cohesive and well focused. I do not see any particular errors, or mis-representations in writing. So, as for the study and its writing, I think it is publishable. So I examined this manuscript from scientific methods side of views. Below are my comments to authors and to editors. You may make revisions if you accept my comments or leave them alone since the comments are more from my personal views.

1. While it is important to continuously build up a profile of the prevalence in literature, reporting prevalence alone or as a main content of introduction for this paper, as presented mostly in statistics terms, seems a bit thin. The whole findings of the study as presented are prevalence rates, however detailed and broken down by the type of mental disorders.

2. Only three countries are included. I understand this is because of the articles selected through a screening process. So it is not authors' purpose to include them only. Is there a way to explain/estimate why other, economically advanced, countries are not included?

3. Readers like me would want to see prevalence rates of each of the countries for a comparison. This will add some contextual information to the paper.

4. As a research who has been working with homeless population, I also like to see a bit comparisons about demographic characteristics across the types of mental disorders, and countries.

Thank you for the opportunity to review this article!

Reviewer #3: This is - in principle - a very useful and important update of the earlier review on mental disorders in people living homeless. However, the paper has two major methodological flaws related to the meta-analysis and meta-regressions that do not allow to proceed with the publication. Firstly, the variable selection procedure via p-value is as outdated as it is statistically wrong. If the authors want to stick to the model selection (there are many pros and cons related to the selection issue), they should use proper software solutions that are available in R metafor. Secondly, and also related to software issues, the authors should use a procedure that accounts for the problem of using multiple effects from the same study/publication. Again, R metafor is able to deal with this problem. In such situations, multilevel models (effects within studies/publications) should be conducted.

In the light of these problems, I suggest a rejection and re-submission after dealing with the issues.

Reviewer #4: This is a well-structured meta-analytic review with robust methodology and profound significance for mental health research and policymaking in homeless populations. The presentation of the findings and articulation of the evidence in the context of homelessness appeared to be excellent. However, there are a few concerns that should be addressed to improve the scholarly value accuracy and implications of this manuscript.

First, the abstract should clearly mention the objective of the review before stepping into the methods. Also, the abstract should inform that it is an updated review; therefore, mentioning the previous review and specifying the timeline of the current would substantially improve the abstract.

Second, the introduction/background does not provide a clear understanding of why a review on high-income countries AND homeless people is required in the first place. It is essential to describe the "need" for a review. The authors may expand the biopsychosocial challenges associated with mental health in homeless people and how they are recognized amongst one of the most marginalized population groups in developed countries. Such explanations, among many others, are likely to inform the readers why this review is important and why we must focus on the evidence available on this critical issue. Also, multiple previous reviews on homelessness and mental health [1-4], not only the one that was published in 2007, should be discussed in the background to offer a broader understanding of the evidence landscape.

Third, the authors should specify which mental disorders were considered before screening the articles. A complete list of disorders should accompany the manuscript, perhaps as supplementary material. Also, reference#22 was cited in the methods section, which was originally published in 1985. The authors may explain why they did not use the most contemporary definitions and categories of mental disorders as stated in DSM-5 or ICD-10. An informed author may wish to understand what disorders/conditions were within and beyond the scope of the current review.

Fourth, the authors should consider sensitivity analyses to examine the effects of individual studies (and their effect sizes) on the pooled estimates for each meta-analytic model. Also, subgroup analyses in this review appeared to be limited to the risk of bias, whereas multiple subgroups could be constructed using variables such as gender (male vs. female), age (young adult vs. older adult), types of homeless (street-living vs. those in shelter homes), comorbidity (healthy vs. those with known medical conditions), geographic locations (homeless in North America vs. in Europe) etc. A set of subgroup analyses would be extremely helpful to interpret the differences in estimates in different subgroups and adopt specific measures to improve their mental health outcomes. This is important because homeless people are not homogenous [5-7]; therefore, their psychosocial stressors are likely to vary, and this must be

recognized while estimating the burden of their mental health problems.

Fifth, the authors should provide explanations/reasons for the excluded studies, at least for those that were excluded during the full-text evaluation. That should inform how many articles were excluded for each specific reason(s).

Sixth, the discussion section of this manuscript could offer more insights on what the current evidence informs about future research priorities. One of the goals of systematic reviews and/or meta-analysis is to identify research gaps and offer guidance on critical areas that require further assessment. Moreover, the interpretation of the evidence should accompany how the practitioners and policymakers can use the evidence in practice. Prevalence estimates can inform psychosocial vulnerabilities in the population of interest and inform the need for action that may address the existing disease burden. Such avenues must be explored in the discussion of the manuscript.

Lastly, the limitations of the review must be revisited and strengthened considering the following issues: a) a limited number of databases searched (with marked overlaps between similar databases such as Medline and PubMed), and b) a lack of reporting the publication bias (can be ignored in the authors provide the funnel plots/Egger's test estimates for publication bias).

References:

1. Ayano G, Belete A, Duko B, Tsegay L, Dachew BA. Systematic review and meta-analysis of the prevalence of depressive symptoms, dysthymia and major depressive disorders among homeless people. BMJ open. 2021 Feb 1;11(2):e040061.

2. Schreiter S, Bermpohl F, Krausz M, Leucht S, Rössler W, Schouler-Ocak M, Gutwinski S. The prevalence of mental illness in homeless people in Germany: A systematic review and meta-analysis. Deutsches Aerzteblatt International. 2017 Oct;114(40):665.

3. Bassuk EL, Richard MK, Tsertsvadze A. The prevalence of mental illness in homeless children: A systematic review and meta-analysis. Journal of the American Academy of Child & Adolescent Psychiatry. 2015 Feb 1;54(2):86-96.

4. Hossain MM, Sultana A, Tasnim S, Fan Q, Ma P, McKyer EL, Purohit N. Prevalence of mental disorders among people who are homeless: An umbrella review. International Journal of Social Psychiatry. 2020 Sep;66(6):528-41.

5. Chamberlain C, MacKenzie D. Understanding contemporary homelessness: Issues of definition and meaning. Australian Journal of Social Issues. 1992 Nov;27(4):274-97.

6. Smith EM, North CS. Not all homeless women are alike: effects of motherhood and the presence of children. Community Mental Health Journal [Internet]. 1994 Dec [cited 2021 Mar 11];30(6):601-10.

7. Institute of Medicine (US) Committee on Health Care for Homeless People. Homelessness, Health, and Human Needs. Washington (DC): National Academies Press (US); 1988. 1, Who Are the Homeless? Available from: https://www.ncbi.nlm.nih.gov/books/NBK218239/

Any attachments provided with reviews can be seen via the following link:

[LINK]

Attachment

Submitted filename: gutwinski.pdf

Click here for additional data file.^{(67.8KB, pdf)}

PLoS Med. 2021 Aug 23;18(8):e1003750. doi: 10.1371/journal.pmed.1003750.r003

Author response to Decision Letter 1

29 Apr 2021

Attachment

Submitted filename: Detailed Response to Reviewers.docx

Click here for additional data file.^{(41.1KB, docx)}

PLoS Med. doi: 10.1371/journal.pmed.1003750.r004

Decision Letter 2

Caitlin Moyer

22 Jul 2021

Dear Dr. Fazel,

Thank you very much for re-submitting your manuscript "The prevalence of mental disorders among homeless people in high-income countries: updated systematic review and meta-regression analysis" (PMEDICINE-D-21-00563R2) for review by PLOS Medicine.

I have discussed the paper with my colleagues and the academic editor and it was also seen again by one of the reviewers. I am pleased to say that provided the remaining editorial and production issues are dealt with we are planning to accept the paper for publication in the journal.

The remaining issues that need to be addressed are listed at the end of this email. Any accompanying reviewer attachments can be seen via the link below. Please take these into account before resubmitting your manuscript:

[LINK]

In revising the manuscript for further consideration here, please ensure you address the specific points made by each reviewer and the editors. In your rebuttal letter you should indicate your response to the reviewers' and editors' comments and the changes you have made in the manuscript. Please submit a clean version of the paper as the main article file. A version with changes marked must also be uploaded as a marked up manuscript file.

Please also check the guidelines for revised papers at http://journals.plos.org/plosmedicine/s/revising-your-manuscript for any that apply to your paper. If you haven't already, we ask that you provide a short, non-technical Author Summary of your research to make findings accessible to a wide audience that includes both scientists and non-scientists. The Author Summary should immediately follow the Abstract in your revised manuscript. This text is subject to editorial change and should be distinct from the scientific abstract.

We expect to receive your revised manuscript within 1 week. Please email us (plosmedicine@plos.org) if you have any questions or concerns.

We ask every co-author listed on the manuscript to fill in a contributing author statement. If any of the co-authors have not filled in the statement, we will remind them to do so when the paper is revised. If all statements are not completed in a timely fashion this could hold up the re-review process. Should there be a problem getting one of your co-authors to fill in a statement we will be in contact. YOU MUST NOT ADD OR REMOVE AUTHORS UNLESS YOU HAVE ALERTED THE EDITOR HANDLING THE MANUSCRIPT TO THE CHANGE AND THEY SPECIFICALLY HAVE AGREED TO IT.

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript.

Please note, when your manuscript is accepted, an uncorrected proof of your manuscript will be published online ahead of the final version, unless you've already opted out via the online submission form. If, for any reason, you do not want an earlier version of your manuscript published online or are unsure if you have already indicated as such, please let the journal staff know immediately at plosmedicine@plos.org.

If you have any questions in the meantime, please contact me or the journal staff on plosmedicine@plos.org.

We look forward to receiving the revised manuscript by Jul 29 2021 11:59PM.

Sincerely,

Caitlin Moyer, Ph.D.

Associate Editor

PLOS Medicine

plosmedicine.org

------------------------------------------------------------

Requests from Editors:

1. Title: Please capitalize the first word of the subtitle, we suggest: “The prevalence of mental disorders among homeless people in high-income countries: An updated systematic review and meta-regression analysis”

2. Abstract: Line 41-42: Please provide slightly more detail on how study quality was assessed.

3. Abstract: Line 54-56: We suggest revising to “Our findings suggest the burden of psychiatric morbidity in homeless persons is substantial…”

4. Author summary: “Why was this study done” Line 68, and Discussion: Line 436 and 512, 514, 518: We suggest replacing “the homeless” with “homeless individuals” or similar.

5. Discussion: Line 477: Please spell out “RCT” in the text, if this is the first mention of the abbreviation.

6. Page 23: Please remove the “Funding” section from the main text and ensure all information is accurately entered in the “Financial Disclosure” section of the manuscript submission form.

7. References: Please double check that all references use the "Vancouver" style for reference formatting, and see our website for other reference guidelines https://journals.plos.org/plosmedicine/s/submission-guidelines#loc-references

Ref 22, 61, 66, 84, 96: Please double check if the reference information is complete. Please check the journal title abbreviation for Reference 102.

8. Figure 2 - 8: If possible, please increase the font size if possible, particularly along the X axis labels.

9. Supporting information files: Please include a “clean” version of each table and S1 Text.

Comments from Reviewers:

Reviewer #1: The authors have addressed my points successfully.

Michael Dewey

Any attachments provided with reviews can be seen via the following link:

[LINK]

PLoS Med. 2021 Aug 23;18(8):e1003750. doi: 10.1371/journal.pmed.1003750.r005

Author response to Decision Letter 2

30 Jul 2021

Attachment

Submitted filename: Detailed Response to Reviewers_2nd_rev.docx

Click here for additional data file.^{(18.9KB, docx)}

PLoS Med. doi: 10.1371/journal.pmed.1003750.r006

Decision Letter 3

Caitlin Moyer

2 Aug 2021

Dear Dr Fazel,

On behalf of my colleagues and the Academic Editor, Vikram Patel, I am pleased to inform you that we have agreed to publish your manuscript "The prevalence of mental disorders among homeless people in high-income countries: An updated systematic review and meta-regression analysis" (PMEDICINE-D-21-00563R3) in PLOS Medicine.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow up email. Please be aware that it may take several days for you to receive this email; during this time no action is required by you. Once you have received these formatting requests, please note that your manuscript will not be scheduled for publication until you have made the required changes.

In the meantime, please log into Editorial Manager at http://www.editorialmanager.com/pmedicine/, click the "Update My Information" link at the top of the page, and update your user information to ensure an efficient production process.

In addition, please complete the following editorial requests:

-Abstract: Line 62: Please remove the funding information from the Abstract at line 62 (“SF is funded by the Wellcome Trust (202836/Z/16/Z)”) , as the study funding information will be included automatically from the Financial Disclosure information entered with the manuscript submission data.

-Methods: Line 213, and Supporting Information Tables: The terms gender and sex are not interchangeable; please use the appropriate term consistently throughout. The term “sex” is used in Table 1. Please replace “gender” with “sex” in this sentence in the Methods and in S4, S7, S8, S9, and S10 Tables for reporting ratio of female to all participants.

-Discussion: Line 415: Please check that the number of studies should be reported here as 39, and the number of included participants should be 8049, as indicated in the Results and Abstract. There is also a typo in Figure 1 where 38 should be 39.

-References: Please change Nov to Apr for Reference 95.

PRESS

We frequently collaborate with press offices. If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximise its impact. If the press office is planning to promote your findings, we would be grateful if they could coordinate with medicinepress@plos.org. If you have not yet opted out of the early version process, we ask that you notify us immediately of any press plans so that we may do so on your behalf.

We also ask that you take this opportunity to read our Embargo Policy regarding the discussion, promotion and media coverage of work that is yet to be published by PLOS. As your manuscript is not yet published, it is bound by the conditions of our Embargo Policy. Please be aware that this policy is in place both to ensure that any press coverage of your article is fully substantiated and to provide a direct link between such coverage and the published work. For full details of our Embargo Policy, please visit http://www.plos.org/about/media-inquiries/embargo-policy/.

Thank you again for submitting to PLOS Medicine. We look forward to publishing your paper.

Sincerely,

Caitlin Moyer, Ph.D.

Associate Editor

PLOS Medicine

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

S1 Table. Database search strings.

(DOCX)

Click here for additional data file.^{(17.3KB, docx)}

S2 Table. PRISMA 2009 checklist.

(DOCX)

Click here for additional data file.^{(24.2KB, docx)}

S3 Table. Studies excluded at full-text screening, with reasons.

(DOCX)

Click here for additional data file.^{(35.4KB, docx)}

S4 Table. Study characteristics.

(DOCX)

Click here for additional data file.^{(27.5KB, docx)}

S5 Table. JBI checklist for prevalence studies.

(DOCX)

Click here for additional data file.^{(20KB, docx)}

S6 Table. Risk of bias tool.

(DOCX)

Click here for additional data file.^{(21.8KB, docx)}

S7 Table. Data basis for meta-analyses and meta-regression analyses.

(DOCX)

Click here for additional data file.^{(30.3KB, docx)}

S8 Table. Univariable regression models.

(DOCX)

Click here for additional data file.^{(16.8KB, docx)}

S9 Table. Results of single factor meta-regression models for affective disorders (pooled).

(DOCX)

Click here for additional data file.^{(13.7KB, docx)}

S10 Table. Results of multiple factor meta-regression for affective disorders (pooled).

(DOCX)

Click here for additional data file.^{(12.9KB, docx)}

S1 Text. Affective disorders.

Results of meta-analysis and meta-regression analysis.

(DOCX)

Click here for additional data file.^{(14.1KB, docx)}

Attachment

Submitted filename: gutwinski.pdf

Click here for additional data file.^{(67.8KB, pdf)}

Attachment

Submitted filename: Detailed Response to Reviewers.docx

Click here for additional data file.^{(41.1KB, docx)}

Attachment

Submitted filename: Detailed Response to Reviewers_2nd_rev.docx

Click here for additional data file.^{(18.9KB, docx)}

Data Availability Statement

All relevant data are within the manuscript and its Supporting Information files.

[pmed.1003750.ref001] 1.United Nations Commission for Social Development. Affordable housing and social protection systems for all to address homelessness. Report of the Secretary-General. E/CN.5/2020/3. New York: United Nations Commission for Social Development; 2019Nov27 [cited 2020 May 10]. Available from: https://undocs.org/en/E/CN.5/2020/3. [Google Scholar]

[pmed.1003750.ref002] 2.Directorate of Employment, Labour and Social Affairs. HC3.1 Homeless population. Paris: Organisation for Economic Co-operation and Development; 2020. [cited 2020 May 3]. Available from: https://www.oecd.org/els/family/HC3-1-Homeless-population.pdf. [Google Scholar]

[pmed.1003750.ref003] 3.Tsai J. Lifetime and 1-year prevalence of homelessness in the US population: results from the National Epidemiologic Survey on Alcohol and Related Conditions-III. J Public Health (Oxf). 2018;40(1):65–74. doi: 10.1093/pubmed/fdx034 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref004] 4.Henry M, Mahathey A, Morrill T, Robinson A, Shivji A, Watt R. The 2018 Annual Homeless Assessment Report (AHAR) to Congress. Part 1: point-in-time estimates of homelessness. Washington (DC): US Department of Housing and Urban Development; 2018Dec [cited 2020 May 10]. Available from: https://www.huduser.gov/portal/sites/default/files/pdf/2018-AHAR-Part-1.pdf. [Google Scholar]

[pmed.1003750.ref005] 5.Willliams SP, Bryant K. Sexually transmitted infection prevalence among homeless adults in the United States: a systematic literature review. Sex Transm Dis. 2018;45(7):494–504. doi: 10.1097/OLQ.0000000000000780 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref006] 6.Topolovec-Vranic J, Ennis N, Colantonio A, Cusimano MD, Hwang SW, Kontos P, et al. Traumatic brain injury among people who are homeless: a systematic review. BMC Public Health. 2012;12(1):1059. doi: 10.1186/1471-2458-12-1059 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref007] 7.Nusselder WJ, Slockers MT, Krol L, Slockers CT, Looman CWN, van Beeck EF. Mortality and life expectancy in homeless men and women in Rotterdam: 2001–2010. PLoS ONE. 2013;8(10):e73979. doi: 10.1371/journal.pone.0073979 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref008] 8.Fazel S, Geddes JR, Kushel M. The health of homeless people in high-income countries: descriptive epidemiology, health consequences, and clinical and policy recommendations. Lancet. 2014;384(9953):1529–40. doi: 10.1016/S0140-6736(14)61132-6 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref009] 9.Bernstein RS, Meurer LN, Plumb EJ, Jackson JL. Diabetes and hypertension prevalence in homeless adults in the United States: a systematic review and meta-analysis. Am J Public Health. 2014;105(2):46–60. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref010] 10.Beijer U, Wolf A, Fazel S. Prevalence of tuberculosis, hepatitis C virus, and HIV in homeless people: a systematic review and meta-analysis. Lancet Infect Dis. 2012;12(11):859–70. doi: 10.1016/S1473-3099(12)70177-9 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref011] 11.Baggett TP, Hwang SW, O’Connell JJ, Porneala BC, Stringfellow EJ, Orav EJ, et al. Mortality among homeless adults in Boston: shifts in causes of death over a 15-year period. JAMA Intern Med. 2013;173(3):189–95. doi: 10.1001/jamainternmed.2013.1604 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref012] 12.Aldridge RW, Story A, Hwang SW, Nordentoft M, Luchenski SA, Hartwell G, et al. Morbidity and mortality in homeless individuals, prisoners, sex workers, and individuals with substance use disorders in high-income countries: a systematic review and meta-analysis. Lancet. 2018;391(10117):241–50. doi: 10.1016/S0140-6736(17)31869-X [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref013] 13.Jones AA, Gicas KM, Seyedin S, Willi TS, Leonova O, Vila-Rodriguez F, et al. Associations of substance use, psychosis, and mortality among people living in precarious housing or homelessness: a longitudinal, community-based study in Vancouver, Canada. PLoS Med. 2020;17(7):e1003172. doi: 10.1371/journal.pmed.1003172 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref014] 14.Nielsen SF, Hjorthøj CR, Erlangsen A, Nordentoft M. Psychiatric disorders and mortality among people in homeless shelters in Denmark: a nationwide register-based cohort study. Lancet. 2011;377(9784):2205–14. doi: 10.1016/S0140-6736(11)60747-2 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref015] 15.Perron BE, Alexander-Eitzman B, Gillespie DF, Pollio D. Modeling the mental health effects of victimization among homeless persons. Soc Sci Med. 2008;67(9):1475–9. doi: 10.1016/j.socscimed.2008.07.012 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref016] 16.Roy L, Crocker AG, Nicholls TL, Latimer EA, Ayllon AR. Criminal behavior and victimization among homeless individuals with severe mental illness: a systematic review. Psychiatr Serv. 2014;65(6):739–50. doi: 10.1176/appi.ps.201200515 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref017] 17.Caton CLM, Dominguez B, Schanzer B, Hasin DS, Shrout PE, Felix A, et al. Risk factors for long-term homelessness: findings from a longitudinal study of first-time homeless single adults. Am J Public Health. 2005;95(10):1753–9. doi: 10.2105/AJPH.2005.063321 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref018] 18.Patterson ML, Somers JM, Moniruzzaman A. Prolonged and persistent homelessness: multivariable analyses in a cohort experiencing current homelessness and mental illness in Vancouver, British Columbia. Ment Health Subst Use. 2012;5(2):85–101. [Google Scholar]

[pmed.1003750.ref019] 19.Skosireva A, O’Campo P, Zerger S, Chambers C, Gapka S, Stergiopoulos V. Different faces of discrimination: perceived discrimination among homeless adults with mental illness in healthcare settings. BMC Health Serv Res. 2014;14(1):376. doi: 10.1186/1472-6963-14-376 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref020] 20.Hossain MM, Sultana A, Tasnim S, Fan Q, Ma P, McKyer ELJ, et al. Prevalence of mental disorders among people who are homeless: an umbrella review. Int J Soc Psychiatry. 2020;66(6):528–41. doi: 10.1177/0020764020924689 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref021] 21.Ayano G, Tesfaw G, Shumet S. The prevalence of schizophrenia and other psychotic disorders among homeless people: a systematic review and meta-analysis. BMC Psychiatry. 2019;19(1):370. doi: 10.1186/s12888-019-2361-7 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref022] 22.Ayano G, Tsegay L, Abraha M, Yohannes K. Suicidal ideation and attempt among homeless people: a systematic review and meta-analysis. Psychiatr Q. 2019;90(4):829–42. doi: 10.1007/s11126-019-09667-8 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref023] 23.Depp CA, Vella L, Orff HJ, Twamley EW. A quantitative review of cognitive functioning in homeless adults. J Nerv Ment Dis. 2015;203(2):126–31. doi: 10.1097/NMD.0000000000000248 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref024] 24.Embleton L, Mwangi A, Vreeman R, Ayuku D, Braitstein P. The epidemiology of substance use among street children in resource‐constrained settings: a systematic review and meta‐analysis. Addiction. 2013;108(10):1722–33. doi: 10.1111/add.12252 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref025] 25.Bassuk EL, Richard MK, Tsertsvadze A. The prevalence of mental illness in homeless children: a systematic review and meta-analysis. J Am Acad Child Adolesc Psychiatry. 2015;54(2):86–96. doi: 10.1016/j.jaac.2014.11.008 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref026] 26.Schreiter S, Bermpohl F, Krausz M, Leucht S, Rössler W, Schouler-Ocak M, et al. The prevalence of mental illness in homeless people in Germany. Dtsch Arztebl Int. 2017;114(40):665–72. doi: 10.3238/arztebl.2017.0665 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref027] 27.Fazel S, Khosla V, Doll H, Geddes J. The prevalence of mental disorders among the homeless in western countries: systematic review and meta-regression analysis. PLoS Med. 2008;5(12):e225. doi: 10.1371/journal.pmed.0050225 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref028] 28.Bäuml J, Brönner M, Baur B, Pitschel-Walz GG, Jahn T, Bäuml J. Die SEEWOLF-Studie: seelische Erkrankungsrate in den Einrichtungen der Wohnungslosenhilfe im Großraum München. Archiv für Wissenschaft und Praxis der sozialen Arbeit. Freiburg im Breisgau: Lambertus-Verlag; 2017. [Google Scholar]

[pmed.1003750.ref029] 29.Laporte A, Vandentorren S, Detrez M-A, Douay C, Le Strat Y, Le Mener E, et al. Prevalence of mental disorders and addictions among homeless people in the greater Paris area, France. Int J Environ Res Public Health. 2018;15(2):241. doi: 10.3390/ijerph15020241 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref030] 30.Williams JBW. The multiaxial system of DSM-III: where did it come from and where should it go?: II. Empirical studies, innovations, and recommendations. Arch Gen Psychiatry. 1985;42(2):181–6. doi: 10.1001/archpsyc.1985.01790250075010 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref031] 31.Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, et al. Meta-analysis of observational studies in epidemiology: a proposal for reporting. JAMA. 2000;283(15):2008–12. doi: 10.1001/jama.283.15.2008 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref032] 32.Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med. 2009;6(7):e1000097. doi: 10.1371/journal.pmed.1000097 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref033] 33.World Bank. World Bank country and lending groups. Washington (DC): World Bank; 2020. [cited 2020 Sep 11]. Available from: https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country-and-lending-groups. [Google Scholar]

[pmed.1003750.ref034] 34.JBI. Critical appraisal tools. Adelaide: University of Adelaide; 2021 [cited 2021 Aug 12]. Available from: https://jbi.global/critical-appraisal-tools.

[pmed.1003750.ref035] 35.Hoy D, Brooks P, Woolf A, Blyth F, March L, Bain C, et al. Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement. J Clin Epidemiol. 2012;65(9):934–9. doi: 10.1016/j.jclinepi.2011.11.014 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref036] 36.Bates D, Chambers J, Dalgaard P, Gentleman R, Hornik K, Ihaka R, et al. R-4.0.4. Comprehensive R Archive Network; 2021. [cited 2021 Apr 21]. Available from: https://cran.r-project.org/. [Google Scholar]

[pmed.1003750.ref037] 37.Van Buuren S, Groothuis-Oudshoorn K. mice: multivariate imputation by chained equations in R. J Stat Softw. 2011Dec12. doi: 10.18637/jss.v045.i03 [DOI] [Google Scholar]

[pmed.1003750.ref038] 38.Calcagno V, de Mazancourt C. glmulti: an R package for easy automated model selection with (generalized) linear models. J Stat Softw. 2010May31. doi: 10.18637/jss.v034.i12 [DOI] [Google Scholar]

[pmed.1003750.ref039] 39.Viechtbauer W. Conducting meta-analyses in R with the metafor package. J Stat Softw. 2010Aug5. doi: 10.18637/jss.v036.i03 [DOI] [Google Scholar]

[pmed.1003750.ref040] 40.Barendregt JJ, Doi SA, Lee YY, Norman RE, Vos T. Meta-analysis of prevalence. J Epidemiol Community Health. 2013;67(11):974–8. doi: 10.1136/jech-2013-203104 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref041] 41.Veroniki AA, Jackson D, Viechtbauer W, Bender R, Bowden J, Knapp G, et al. Methods to estimate the between-study variance and its uncertainty in meta-analysis. Res Synth Methods. 2016;7(1):55–79. doi: 10.1002/jrsm.1164 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref042] 42.Riley RD, Higgins JPT, Deeks JJ. Interpretation of random effects meta-analyses. BMJ. 2011;342:964–7. doi: 10.1136/bmj.d549 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref043] 43.Viechtbauer W. Package ‘metafor.’ Version 2.4–0. Comprehensive R Archive Network; 2020 [cited 2021 Apr 21]. Available from: https://cran.r-project.org/web/packages/metafor/metafor.pdf.

[pmed.1003750.ref044] 44.Higgins JPT, Thompson SG, Spiegelhalter DJ. A re-evaluation of random-effects meta-analysis. J R Stat Soc Ser A Stat Soc. 2009;172(1):137–59. doi: 10.1111/j.1467-985X.2008.00552.x [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref045] 45.Anderson-Sprecher R. Model comparisons and R^2. Am Stat. 1994;48(2):113–7. [Google Scholar]

[pmed.1003750.ref046] 46.Little RJ, D’Agostino R, Cohen ML, Dickersin K, Emerson SS, Farrar JT, et al. The prevention and treatment of missing data in clinical trials. N Engl J Med. 2012;367(14):1355–60. doi: 10.1056/NEJMsr1203730 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref047] 47.Azur MJ, Stuart EA, Frangakis C, Leaf PJ. Multiple imputation by chained equations: what is it and how does it work? Int J Methods Psychiatr Res. 2011;20(1):40–9. doi: 10.1002/mpr.329 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref048] 48.Jakobsen JC, Gluud C, Wetterslev J, Winkel P. When and how should multiple imputation be used for handling missing data in randomised clinical trials—a practical guide with flowcharts. BMC Med Res Methodol. 2017;17(1):162. doi: 10.1186/s12874-017-0442-1 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref049] 49.Sclare PD. Psychiatric disorder among the homeless in Aberdeen. Scott Med J. 1997;42(6):173–7. doi: 10.1177/003693309704200605 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref050] 50.Salize HJ, Dillmann-Lange C, Stern G, Kentner-Figura B, Stamm K, Rossler W, et al. Alcoholism and somatic comorbidity among homeless people in Mannheim, Germany. Addiction. 2002;97(12):1593–600. doi: 10.1046/j.1360-0443.2002.00235.x [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref051] 51.Salize HJ, Horst A, Dillmann-Lange C, Killmann U, Stern G, Wolf I, et al. Needs for mental health care and service provision in single homeless people. Soc Psychiatry Psychiatr Epidemiol. 2001;36(4):207–16. doi: 10.1007/s001270170065 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref052] 52.Reinking DP, Wolf JR, Kroon H. Hoge prevalentie van psychische stoornissen en verslavingsproblemen bij daklozen in de stad Utrecht. Ned Tijdschr Geneeskd. 2001;145(24):1161–6. [PubMed] [Google Scholar]

[pmed.1003750.ref053] 53.Nishio A, Yamamoto M, Horita R, Sado T, Ueki H, Watanabe T, et al. Prevalence of mental illness, cognitive disability, and their overlap among the homeless in Nagoya, Japan. PLoS ONE. 2015;10(9):e0138052. doi: 10.1371/journal.pone.0138052 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref054] 54.Morikawa S, Uehara R, Okuda K, Shimizu H, Nakamura Y. [Prevalence of psychiatric disorders among homeless people in one area of Tokyo.] Nihon Koshu Eisei Zasshi. 2011;58(5):331–9. [PubMed] [Google Scholar]

[pmed.1003750.ref055] 55.Madianos MG, Chondraki P, Papadimitriou GN. Prevalence of psychiatric disorders among homeless people in Athens area: a cross-sectional study. Soc Psychiatry Psychiatr Epidemiol. 2013;48(8):1225–34. doi: 10.1007/s00127-013-0674-2 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref056] 56.Längle G, Egerter B, Albrecht F, Petrasch M, Buchkremer G. Prevalence of mental illness among homeless men in the community. Soc Psychiatry Psychiatr Epidemiol. 2005;40(5):382–90. doi: 10.1007/s00127-005-0902-5 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref057] 57.Krausz RM, Clarkson AF, Strehlau V, Torchalla I, Li K, Schuetz CG. Mental disorder, service use, and barriers to care among 500 homeless people in 3 different urban settings. Soc Psychiatry Psychiatr Epidemiol. 2013;48(8):1235–43. doi: 10.1007/s00127-012-0649-8 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref058] 58.Kovess V, Mangin Lazarus C. The prevalence of psychiatric disorders and use of care by homeless people in Paris. Soc Psychiatry Psychiatr Epidemiol. 1999;34(11):580–7. doi: 10.1007/s001270050178 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref059] 59.Whitbeck LB, Armenta BE, Welch-Lazoritz ML. Borderline personality disorder and Axis I psychiatric and substance use disorders among women experiencing homelessness in three US cities. Soc Psychiatry Psychiatr Epidemiol. 2015;50(8):1285–91. doi: 10.1007/s00127-015-1026-1 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref060] 60.Koegel P, Burnam MA, Farr RK. The prevalence of specific psychiatric disorders among homeless individuals in the inner city of Los Angeles. Arch Gen Psychiatry. 1988;45(12):1085–92. doi: 10.1001/archpsyc.1988.01800360033005 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref061] 61.Kershaw A, Singleton N, Meltzer H. Survey of the health and well-being of homeless people in Glasgow. Int Rev Psychiatry. 2003;15(1–2):141–3. doi: 10.1080/0954026021000046065 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref062] 62.Hynes F, Kilbride K, Fenton J. A survey of mental disorder in the long-term, rough sleeping, homeless population of inner Dublin. Ir J Psychol Med. 2019;36(1):19–22. doi: 10.1017/ipm.2018.23 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref063] 63.Herrman H, McGorry P, Bennett P, van Riel R, Singh B. Prevalence of severe mental disorders in disaffiliated and homeless people in inner Melbourne. Am J Psychiatry. 1989;146(9):1179–84. doi: 10.1176/ajp.146.9.1179 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref064] 64.Haugland G, Siegel C, Hopper K, Alexander MJ. Mental illness among homeless individuals in a suburban county. Psychiatr Serv. 1997;48(4):504–9. doi: 10.1176/ps.48.4.504 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref065] 65.Greifenhagen A, Fichter M. Mental illness in homeless women: an epidemiological study in Munich, Germany. Eur Arch Psychiatry Clin Neurosci. 1997;247(3):162–72. doi: 10.1007/BF03033070 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref066] 66.Gill B, Meltzer H, Hinds K. The prevalence of psychiatric morbidity among homeless adults. Int Rev Psychiatry. 2003;15(1–2):134–40. doi: 10.1080/0954026021000046056 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref067] 67.Geddes J, Newton R, Young G, Bailey S, Freeman C, Priest R. Comparison of prevalence of schizophrenia among residents of hostels for homeless people in 1966 and 1992. BMJ. 1994;308(6932):816–9. doi: 10.1136/bmj.308.6932.816 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref068] 68.Freeman SJ, Formo A, Alampur AG, Sommers AF. Psychiatric disorder in a skid-row mission population. Compr Psychiatry. 1979;20(5):454–62. doi: 10.1016/0010-440x(79)90031-2 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref069] 69.Fischer PJ, Shapiro S, Breakey WR, Anthony JC, Kramer M. Mental health and social characteristics of the homeless: a survey of mission users. Am J Public Health. 1986;76(5):519–24. doi: 10.2105/ajph.76.5.519 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref070] 70.Weller BG, Weller MP, Coker E, Mahomed S. Crisis at Christmas 1986. Lancet. 1987;1(8532):553–4. doi: 10.1016/s0140-6736(87)90187-5 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref071] 71.Fichter MM, Quadflieg N. Prevalence of mental illness in homeless men in Munich, Germany: results from a representative sample. Acta Psychiatr Scand. 2001;103(2):94–104. doi: 10.1034/j.1600-0447.2001.00217.x [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref072] 72.Eikelmann B, Inhester ML, Reker T. Psychische Störungen bei nichtsesshaften Männern. Defizite in der psychiatrischen Versorgung. Sozialpsychiatr Informationen. 1992;29–32. [Google Scholar]

[pmed.1003750.ref073] 73.Dufeu P, Podschus J, Schmidt LG. Alkoholabhängigkeit bei männlichen Wohnungslosen. Häufigkeit, Ausprägung und Determinanten. Nervenarzt. 1996;67(11):930–4. [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref074] 74.Doutney CP, Buhrich N, Virgona A, Cohen A, Daniels P. The prevalence of schizophrenia in a refuge for homeless men. Aust N Z J Psychiatry. 1985;19(3):233–8. doi: 10.3109/00048678509158828 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref075] 75.Conolly AJ, Cobb-Richardson P, Ball SA. Personality disorders in homeless drop-in centre clients. J Pers Disord. 2008;22(6):573–88. doi: 10.1521/pedi.2008.22.6.573 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref076] 76.Briner D, Jäger M, Kawohl W, Baumgartner-Nietlisbach G. Mental disorder and self-rated health among homeless people in Zurich: first epidemiological data from Switzerland. Psychiatr Prax. 2017;44(6):339–47. doi: 10.1055/s-0042-111742 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref077] 77.Bassuk EL, Rubin L, Lauriat A. Is homelessness a mental health problem? Am J Psychiatry. 1984;141(12):1546–50. doi: 10.1176/ajp.141.12.1546 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref078] 78.Adams CE, Pantelis C, Duke PJ, Barnes TRE. Psychopathology, social and cognitive functioning in a hostel for homeless women. Br J Psychiatry. 1996;168(1):82–6. doi: 10.1192/bjp.168.1.82 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref079] 79.North CS, Eyrich-Garg KM, Pollio DE, Thirthalli J. A prospective study of substance use and housing stability in a homeless population. Soc Psychiatry Psychiatr Epidemiol. 2009;45(11):1055–62. doi: 10.1007/s00127-009-0144-z [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref080] 80.Völlm B, Becker H, Kunstmann W. Psychiatrische Morbidität bei allein stehenden wohnungslosen Männern. Psychiatr Prax. 2004;31(5):236–40. doi: 10.1055/s-2003-815014 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref081] 81.Torchalla I, Albrecht F, Buchkremer G, Längle G. Wohnungslose Frauen mit psychischer Erkrankung—eine Feldstudie. Psychiatr Prax. 2004;31(05):228–35. [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref082] 82.Timms PW, Fry AH. Homelessness and mental illness. Health Trends. 1989;21(3):70–1. [PubMed] [Google Scholar]

[pmed.1003750.ref083] 83.Susser E, Struening EL, Conover S. Psychiatric problems in homeless men. Lifetime psychosis, substance use, and current distress in new arrivals at New York City shelters. Arch Gen Psychiatry. 1989;46(9):845–50. doi: 10.1001/archpsyc.1989.01810090087012 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref084] 84.Smith EM, North CS, Spitznagel EL. Alcohol, drugs, and psychiatric comorbidity among homeless women: an epidemiologic study. J Clin Psychiatry. 1993;54(3):82–7. [PubMed] [Google Scholar]

[pmed.1003750.ref085] 85.Smith EM, North CS, Spitznagel EL. A systematic study of mental illness, substance abuse, and treatment in 600 homeless men. Ann Clin Psychiatry. 1992;4(2):111–20. [Google Scholar]

[pmed.1003750.ref086] 86.Wittchen H-U, Jacobi F. Size and burden of mental disorders in Europe—a critical review and appraisal of 27 studies. Eur Neuropsychopharmacol. 2005;15(4):357–76. doi: 10.1016/j.euroneuro.2005.04.012 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref087] 87.Merikangas KR, McClair VL. Epidemiology of substance use disorders. Hum Genet. 2012;131(6):779–89. doi: 10.1007/s00439-012-1168-0 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref088] 88.Adams M, Effertz T. Effective prevention against risky underage drinking—the need for higher excise taxes on alcoholic beverages in Germany. Alcohol Alcohol. 2010;45(4):387–94. doi: 10.1093/alcalc/agq031 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref089] 89.North CS, Pollio DE, Smith EM, Spitznagel EL. Correlates of early onset and chronicity of homelessness in a large urban homeless population. J Nerv Ment Dis. 1998;186(7):393–400. doi: 10.1097/00005053-199807000-00002 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref090] 90.Stein JA, Dixon EL, Nyamathi AM. Effects of psychosocial and situational variables on substance abuse among homeless adults. Psychol Addict Behav. 2008;22(3):410–6. doi: 10.1037/0893-164X.22.3.410 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref091] 91.Aubry T, Duhoux A, Klodawsky F, Ecker J, Hay E. A longitudinal study of predictors of housing stability, housing quality, and mental health functioning among single homeless individuals staying in emergency shelters. Am J Community Psychol. 2016;58(1–2):123–35. doi: 10.1002/ajcp.12067 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref092] 92.Amore K, Baker M, Howden-Chapman P. The ETHOS definition and classification of homelessness: an analysis. Eur J Homelessness. 2011;5(2):19–37. [Google Scholar]

[pmed.1003750.ref093] 93.Hasin DS, Sarvet AL, Meyers JL, Saha TD, Ruan WJ, Stohl M, et al. Epidemiology of adult DSM-5 major depressive disorder and its specifiers in the United States. JAMA Psychiatry. 2018;75(4):336–46. doi: 10.1001/jamapsychiatry.2017.4602 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref094] 94.Schreiter S, Bermpohl F, Schouler-Ocak M, Krausz R, Rössler W, Heinz A, et al. Bank account ownership and access among in-patients in psychiatric care in Berlin, Germany—a cross-sectional patient survey. Front Psychiatry. 2020;11:508. doi: 10.3389/fpsyt.2020.00508 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref095] 95.Schreiter S, Fritz FD, Rössler W, Majić T, Schouler-Ocak M, Krausz MR, et al. [Housing Situation Among People with Substance Use Disorder in a Psychiatric Centre in Berlin, Germany—A Cross-Sectional Patient Survey.] Psychiatr Prax. 2021;48:156–60. doi: 10.1055/a-1290-5091 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref096] 96.Schreiter S, Heidrich S, Heinz A, Rössler W, Krausz RM, Schouler-Ocak M, et al. [Debts, loans and unpaid bills among day patients and inpatients in psychiatric care in Berlin, Germany.] Nervenarzt. 2020Oct14. doi: 10.1007/s00115-020-01013-9 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref097] 97.Schreiter S, Heidrich S, Zulauf J, Saathoff U, Brückner A, Majic T, et al. Housing situation and healthcare for patients in a psychiatric centre in Berlin, Germany: a cross-sectional patient survey. BMJ Open. 2019;9(12):e032576. doi: 10.1136/bmjopen-2019-032576 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref098] 98.Currie LB, Patterson ML, Moniruzzaman A, McCandless LC, Somers JM. Examining the relationship between health-related need and the receipt of care by participants experiencing homelessness and mental illness. BMC Health Serv Res. 2014;14:404. doi: 10.1186/1472-6963-14-404 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref099] 99.Desai MM, Rosenheck RA. Unmet need for medical care among homeless adults with serious mental illness. Gen Hosp Psychiatry. 2005;27(6):418–25. doi: 10.1016/j.genhosppsych.2005.06.003 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref100] 100.Chondraki P, Madianos MG, Dragioti E, Papadimitriou GN. Homeless mentally ill in Athens area: a cross-sectional study on unmet needs and help-seeking. Int J Soc Psychiatry. 2013;60(6):544–53. doi: 10.1177/0020764013503150 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref101] 101.Clarke GN, Herinckx HA, Kinney RF, Paulson RI, Cutler DL, Lewis K, et al. Psychiatric hospitalizations, arrests, emergency room visits, and homelessness of clients with serious and persistent mental illness: findings from a randomized trial of two ACT programs vs. usual care. Ment Health Serv Res. 2000;2(3):155–64. doi: 10.1023/a:1010141826867 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref102] 102.Stergiopoulos V, Hwang SW, Gozdzik A, Nisenbaum R, Latimer E, Rabouin D, et al. Effect of scattered-site housing using rent supplements and intensive case management on housing stability among homeless adults with mental illness: a randomized trial. JAMA. 2015;313(9):905–15. doi: 10.1001/jama.2015.1163 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref103] 103.Rosenheck R, Kasprow W, Frisman L, Liu-Mares W. Cost-effectiveness of supported housing for homeless persons with mental illness. Arch Gen Psychiatry. 2003;60(9):940–51. doi: 10.1001/archpsyc.60.9.940 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref104] 104.Herman D, Opler L, Felix A, Valencia E, Wyatt RJ, Susser E. A critical time intervention with mentally iII homeless men: Impact on psychiatric symptoms. J Nerv Ment Dis. 2000;188(3):135–40. doi: 10.1097/00005053-200003000-00002 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref105] 105.Perri M, Dosani N, Hwang SW. COVID-19 and people experiencing homelessness: challenges and mitigation strategies. CMAJ. 2020;192(26):e716–9. doi: 10.1503/cmaj.200834 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref106] 106.Ministry of Housing, Communities & Local Government, Jenrick R. 6,000 new supported homes as part of landmark commitment to end rough sleeping. London: Ministry of Housing, Communities & Local Government; 2020May24 [cited 2021 Jan 1]. Available from: https://www.gov.uk/government/news/6-000-new-supported-homes-as-part-of-landmark-commitment-to-end-rough-sleeping. [Google Scholar]

[pmed.1003750.ref107] 107.Deutsche Welle. Berlin opens first hostel for the homeless amid coronavirus pandemic. Deutsche Welle. 2020 Mar 31 [cited 2021 Jan 2]. Available from: https://www.dw.com/en/berlin-opens-first-hostel-for-the-homeless-amid-coronavirus-pandemic/a-52972263.

[pmed.1003750.ref108] 108.Bowen M, Marwick S, Marshall T, Saunders K, Burwood S, Yahyouche A, et al. Multimorbidity and emergency department visits by a homeless population: a database study in specialist general practice. Br J Gen Pract. 2019;69(685):e515–25. doi: 10.3399/bjgp19X704609 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pmed.1003750.ref109] 109.Raphael R-W, Caroline S, Dan L, Megan A, Briony H. Premature frailty, geriatric conditions and multimorbidity among people experiencing homelessness: a cross-sectional observational study in a London hostel. Housing Care Support. 2020;23(3–4):77–91. [Google Scholar]

[pmed.1003750.ref110] 110.Abdu L, Withers J, Habib AG, Mijinyawa MS, Yusef SM. Disease pattern and social needs of street people in the race course area of Kano, Nigeria. J Health Care Poor Underserved. 2013;24(1):97–105. doi: 10.1353/hpu.2013.0010 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref111] 111.Mathebula SD, Ross E. Realizing or relinquishing rights? Homeless youth, their life on the streets and their knowledge and experience of health and social services in Hillbrow, South Africa. Soc Work Health Care. 2013;52(5):449–66. doi: 10.1080/00981389.2012.742483 [DOI] [PubMed] [Google Scholar]

[pmed.1003750.ref112] 112.Agans RP, Jefferson MT, Bowling JM, Zeng D, Yang J, Silverbush M. Enumerating the hidden homeless: Strategies to estimate the homeless gone missing from a point-in-time count. J Off Stat. 2014;30(2):215–29. [Google Scholar]

[pmed.1003750.ref113] 113.Neupert P. Statistikbericht 2017. Berlin: Bundesarbeitsgemeinschaft Wohnungslosenhilfe. 2018. [cited 2020 Jul 18]. Available from: https://www.bagw.de/fileadmin/bagw/media/Doc/STA/STA_Statistikbericht_2017.pdf. [Google Scholar]

PERMALINK

The prevalence of mental disorders among homeless people in high-income countries: An updated systematic review and meta-regression analysis

Stefan Gutwinski

Stefanie Schreiter

Karl Deutscher

Seena Fazel

Roles

Abstract

Background

Methods and findings

Conclusions

Trial registration

Author summary

Why was this study done?

What did the researchers do and find?

What do these findings mean?

Introduction

Methods

Search strategy

Eligibility criteria and study selection

Data collection and quality assessment

Statistical analysis

Results

Description of included studies

Fig 1. Screening process.

Any current mental disorders

Fig 2. Forest plot of prevalence estimates of any current mental disorder.

Table 1. Study-level factors associated with between-study heterogeneity in multivariable meta-regression.

Schizophrenia spectrum disorders

Fig 3. Forest plot of prevalence estimates of schizophrenia spectrum disorders.

Major depression

Fig 4. Forest plot of prevalence estimates of major depression.

Bipolar disorder

Fig 5. Forest plot of prevalence estimates of bipolar disorder.

Alcohol use disorders

Fig 6. Forest plot of prevalence estimates of alcohol use disorders.

Drug use disorders

Fig 7. Forest plot of prevalence estimates of drug use disorders.

Personality disorders

Fig 8. Forest plot of prevalence of personality disorders.

Discussion

Supporting information

Acknowledgments

Abbreviations

Data Availability

Funding Statement

References

Decision Letter 0

Caitlin Moyer

Roles

Decision Letter 1

Caitlin Moyer

Roles

Author response to Decision Letter 1

Decision Letter 2

Caitlin Moyer

Roles

Author response to Decision Letter 2

Decision Letter 3

Caitlin Moyer

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

Similar articles

Cited by other articles

Links to NCBI Databases