Assessment of functional disability and associated factors among people with severe mental illness attending care at public hospitals in Harar town, Eastern Ethiopia: a cross-sectional study

Abstract

Objective

This study aimed to assess functional disability and associated factors among people with severe mental illness attending public hospitals in Harar town, Eastern Ethiopia.

Setting

An institution-based cross-sectional study was conducted in public hospitals found in Harar town, Eastern Ethiopia, from 1 April to 10 May 2023.

Participants

A total of 342 patients with severe mental illness attending public hospitals in Harar town, Eastern Ethiopia, were included.

Outcome measure

The main outcome of this study was functional disability, which was measured using a 12-item version of the WHO Disability Assessment Schedule.

Results

In this study, the mean (±) score of functional disability among patients with severe mental illness was 31.8 (±9.6) (95% CI: 30.7 to 32.8). The multiple linear regression model revealed that unemployment (β: 1.93; 95% CI: 0.28 to 3.59), total illness duration (5–10 years and above 10 years) (β: 3.71; 95% CI: 1.95 to 5.48 and β: 4.51; 95% CI: 2.41 to 6.62, respectively), age at illness onset (β: −0.37; 95% CI: −0.45 to −0.28), having drug side effects (β: 3.05; 95% CI: 1.46 to 4.63), medication non-adherence (β: 6.15; 95% CI: 4.56 to 7.73) and having high perceived stigma (β: 2.27; 95% CI: 0.72 to 3.82) were significantly associated with functional disability.

Conclusion

Patients with severe mental illness had a high mean functional disability score. Unemployment, age at onset of mental illness, total duration of illness, medication side effects, medication non-adherence and higher perceived stigma were factors that were associated with functional disability. Given the mean functional disability score observed among respondents, a multipronged intervention strategy that prioritises early detection and management of severe mental illness, particularly targeting individuals at risk, is recommended to mitigate disability and enhance quality of life.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• A multicentre study was carried out to ensure the representativeness and generalisability of the findings.

• A valid data collection tool, the WHO Disability Assessment Schedule, which has a high internal consistency, was used.

• This study also has some flaws, including social desirability bias due to the interviewer-administered data collection method.

• The study’s cross-sectional nature prevented it from accurately capturing the cause-and-effect relationship of the outcome variable.

Introduction

Severe mental illness (SMI) is a long-term mental, behavioural or emotional disorder that results in severe functional disability, which can significantly limit or interfere with one or more major aspects of everyday living.¹

Among the mental illnesses considered SMIs are schizophrenia, bipolar disorder and major depressive disorder.² A functional disability is difficulty functioning at the body, personal or societal levels in one or more life domains, as experienced by a person with a health condition in interaction with contextual factors.³ Regardless of the use of pharmacological and psychosocial therapies, SMIs still rank among the leading causes of disability.⁴

According to the WHO, mental illnesses accounted for 25.3–33.5% of all years lived with a disability in low- and middle-income countries.^{5 6} In the USA, 14.2 million persons, who are 18 years and older, suffer from SMI, making up about 5.6% of the total population.⁷ Mental illness accounts for 31% of the total global functional disability; among these, major depression disorder (11.8%), schizophrenia (2.8%) and bipolar disorder (2.4%).⁸ The literature in Africa showed that the prevalence of functional disability among patients with SMI ranges from 40.6% to 78%.^{9 10} In Ethiopia, studies showed that the magnitude of functional disability among patients with SMI ranges from 41.7% to 88.1%.^{11 12}

Determinants strongly linked with functional disability among people with SMI include sociodemographic characteristics such as male gender, older age, being single, rural residence, jobless status and lower socioeconomic status.13,15 Illness-related characteristics such as severity of symptoms, insidious onset of symptoms, long duration of untreated illness, relapse, comorbid substance abuse, medication side effects, psychotic symptoms, admission history, younger age of onset, duration of treatment, type of disorder and non-adherence are also mentioned as predictors of disability.16,18 Moreover, lack of social support, poor self-esteem and stigma are social factors that are associated with higher disability among patients with SMI.^{9 18 19}

A patient with SMI’s functioning is seriously affected because the disorder makes it harder for them to perform their basic tasks, self-care and medical care, further worsening their physical health and producing a vicious cycle of disability.²⁰ As a consequence, patients face difficulty in succeeding at school, obtaining or maintaining a job, having social relationships, living independently and, for some, even taking care of their basic daily needs.^{20 21}

A deficit in patients’ ability to care for themselves and to meet the expectations of others is the root challenge faced by patients with SMI.²¹ The impacts of mental illness-related disability are not limited to the individual but rather passed down to the whole family and society; they cause families to experience stress, financial issues and discrimination. Excluding persons with disabilities from actively participating in communal life comes at a tremendous cost to society, which frequently results in decreased production and lost human potential, which has an unfavourable effect on social and economic development.^{22 23}

Assessment of functional disability among patients with SMI in Ethiopia is crucial due to several factors, including low mental health care-seeking behaviours, lack of awareness regarding medication adherence and higher stigma, which can interfere with functionality.²⁴

Despite this significant functional disability resulting from SMI, there are few data available on functional disability in patients with SMI in Ethiopia. Therefore, this study aimed to assess functional disabilities and their associated factors among patients with SMI, and it has a crucial role in overcoming functional disabilities among patients with SMI.

Materials and methods

Study area and period

The study was conducted in Harar, the capital city of Harari Regional State. Harari Regional State is one of the eleven regions in Ethiopia, located in the eastern part of the country, 525 km from Addis Ababa, the capital city of Ethiopia. The Harari Region is divided into six urban and three rural administrative districts in accordance with the present administrative system. According to the 2015 national population census, the region had 183 344 people overall, 99 321 (54.2%) of whom lived in cities and 84 023 (45.8%) lived in rural areas.²⁵

According to the Harari regional health bureau, there are two public, one police and two private hospitals. There are also eight (four urban and four rural) health centres, 19 health posts and 10 private clinics in the region.²⁵ The study was conducted in the Hiwot Fana Specialised University Hospital, one of Harari Regional State’s public hospitals. It receives an estimated 529 SMI patient flows per month. The other was Jugal Hospital, which receives 185 SMI patient flows per month. The study was carried out from 1 April to 10 May 2023.

Study design and population

An institution-based cross-sectional study design was employed. All patients with SMIs who have been receiving care at the psychiatry outpatient department of the public hospitals were the source of population. Patients with SMI who had been receiving care at the psychiatry outpatient department of the public hospitals and were available during the data collection period were the study participants. In addition, the study included patients with SMIs receiving care at public hospitals’ psychiatry outpatient departments, aged 18 years and above, with regular follow-up and a Diagnostic Statistical Manual of the American Psychiatric Association (DSM-5) diagnosis of schizophrenia, bipolar disorder and major depressive disorder and excluded those with poor insight or communication difficulties or who were acutely ill.

Sample size determination and sampling procedure

A single mean population formula was employed to calculate the sample size needed for this study . In this study, we used the mean and SD from a study done in Butajira, which is a functional disability mean of 22.3 with a SD of 9.0.²⁶

Therefore, n${\displaystyle =\frac{{\left(1.96\right)}^2}{{\left(1\right)}^2}{\left(9\right)}^2}$=311.

By adding a 10% non-response rate, the calculated final sample size was 342.

In the town, there were two public hospitals that provided mental health services. Therefore, for the sampling, the estimated sample was allocated proportionally to each hospital based on the number of patients attending the psychiatric outpatient department. Then, a systematic random sampling technique was used to collect the required sample size. The sampling interval (k) was determined for each hospital by dividing the study population by the sample size, which was K1=687/253 ≈ 2 and K2=241/89 ≈ 2. Therefore, patients were interviewed at every two intervals in each hospital, and the first participant was selected randomly.

Measurement and data collection tools

The data were collected using a structured questionnaire in the Amharic and Afan Oromo versions of the tool. The questionnaire has five sections, which include sociodemographic characteristics such as age, sex, marital status and the like. The outcome variable was functional disability, which was assessed using the 12-item version of the WHO-Disability Assessment Schedule (DAS), a fully structured disability assessment tool that assessed an individual’s difficulty with performing various daily activities for the past 30 days and the data were collected through face-to-face interview in this study. The items were scored by a 5-point Likert scale ranging from none to extreme: ‘none (1)’, ‘mild (2)’, ‘moderate (3)’, ‘severe (4)’, and ‘extreme/cannot do (5)’ with a maximum score of 60, and a higher score indicates increased disability.²⁷

The tool was validated in rural Ethiopia, in the Butajira General Hospital psychiatric unit, with patients with SMI, and it has an excellent internal consistency with a Cronbach’s alpha scale of α=0.98.²⁸ In this study, the internal consistency of the 12-item version of WHO-DAS was a Cronbach’s alpha of 0.88.

We also evaluated clinical factors, such as medication adherence, using the Medication Adherence Rating Scale (MARS).²⁹ Others, such as previous suicide attempts and the use of traditional treatments, were determined through yes/no questions. Furthermore, factors like diagnosis type, medication type, age at the onset of illness, total duration of illness, number of relapses, history of hospital admissions, duration of untreated illness, history of medication side effects and presence of chronic medical conditions were assessed through a review of medical records.

Alcohol, Smoking and Substance Involvement Screening Test, a quick screening tool developed and validated by the WHO, was used to assess the study participant’s current (3 months) and ever use of psychoactive substances.³⁰

From the psychosocial factors, social support was assessed by the OSLO-3-item social support scale, which is a 3-item questionnaire extensively used in Ethiopia in community as well as institution-based studies to assess social support and has been used in several studies.^{31 32}

Additionally, perceived stigma was measured using a 12-item Perceived Devaluation and Discrimination (PDD) scale questionnaire. It was used to measure the extent to which a person believes that most people are devalued and discriminated against because of psychiatric problems. Each item of PDD is rated on a 4-point Likert scale, which ranges from strongly disagree to strongly agree (1 = strongly disagree, 2 = disagree, 3 = agree and 4 = strongly agree).^{33 34}

Data were collected through face-to-face interviews using a structured questionnaire by four BSc psychiatric nurses, supervised by two MSc psychiatry professionals and the principal investigator. The data collectors and the supervisor received training on the consent form, maintaining confidentiality, handling ethical issues, the study purpose, interacting with participants, controlling missing data and overall data collection procedures before the data collection period.

Operational definition

SMI: the clinical diagnosis of either schizophrenia, bipolar disorder or major depressive disorder based on the DSM-5.³⁵

Disability: higher scores on the WHODAS correspond to increased disability.²⁷

Social support: the OSLO-3 social support scale, a sum score scale, divides support into three categories: 3–8 poor support, 9–11 moderate support and 12–14 strong support.³⁶

Perceived stigma: according to the PDD scale, participants who scored equal to or greater than the mean score are considered to have high perceived stigma.³⁴

Current use of substance: using at least one of any specific substances for non-medical purposes within the last 3 months (alcohol, khat, tobacco or others).³⁰

Ever use of substance: using at least one of any specific substances for non-medical purposes at least once in a lifetime (alcohol, khat, tobacco or others).³⁰

Medication adherence: from the MARS, a total score of <6 was considered non-adherent.²⁹

Data quality assurance and management

The questionnaire was initially prepared in English and then translated into Amharic and Afan Oromo by two language experts appropriate for the participants. Training was given for 1 day to data collectors and supervisors, then a pretest was conducted at Delchora Hospital on 5% of the study population, which was 17 patients, and the WHODAS Cronbach’s alpha value was 0.88 in the pretest of this study. Throughout the course of the data collection, data collectors were supervised at each site, and regular meetings were held between the data collector, supervisor and principal investigator. The collected data were reviewed and checked for completeness and relevance by supervisors and the principal investigator each day.

Statistical analysis

The data was checked, coded and entered into Epi-Data V.4.6 before being exported to Stata V.14 for analysis. Descriptive statistics such as percentages, means and SD were used to summarise the data. Tables and graphs were also used for data presentation. Simple and multiple linear regressions have been employed to identify the factors associated with the outcome variables. The linearity assumption was checked by a scatter plot; homogeneity of variances was checked by scatter plots, and there was no clear pattern on the scatter plot. The skewness ranged between ±1, which was taken as normally distributed, and all variables satisfied assumptions of normality. Variables with a p value of <0.2 during the simple linear regression were selected for multiple linear regression and a p value less than 0.05 was considered statistically significant in multiple linear regression. The model fitness was computed and found to be statistically significant at F=6.75, p value<0.001, R²=0.501 and adjusted R²=0.476. Multicollinearity was checked, and maximum was not evident in the variance inflation factor. Un-standardised beta coefficients with a 95% CI were used to assess the level of association and statistical significance in multiple linear regression analysis.

Patient and public health involvement

None.

Results

Sociodemographic characteristics of the participants

From a total of 342 approached samples, 332 eligible patients diagnosed with SMI were included in the study, which provided a response rate of 97.1%. The participants’ mean age was 35.03 years with an SD of ±10.94, with the minimum and maximum ages of 18 years and 68 years, respectively. Of the total participants, most of them, 197 (59.3%), were males. Nearly half (45.2%) of participants were married, and more than one-third, 122 (36.8%) of them were unable to read and write. More than two-thirds, 227 (68.4%), of respondents were employed, and most of the participants were living in urban areas, 198 (59.6%). About three-quarters, 251 (75.6%), of participants were living with their family (table 1).

Table 1. Sociodemographic characteristics of patients with severe mental illness attending public hospitals in Harar town, Eastern Ethiopia, 2023 (n=332).

Variables	Category	Frequency (n)	Percentage (%)
Age	Mean=35.03, SD = ±10.94
Sex	Male	197	59.3
	Female	135	40.7
Marital status	Single	127	38.3
	Married	150	45.2
	Divorced	43	12.9
	Widowed	12	3.6
Educational status	Unable to read and write	122	36.8
	Able to read and write	58	17.5
	Primary school	85	25.6
	Secondary school	42	12.6
	College and above	25	7.5
Job status	Employed	227	68.4
	Unemployed	105	31.6
Residence	Urban	198	59.6
	Rural	134	40.4
Living arrangement	Live with family	251	75.6
	Alone	66	19.9
	Others	15	4.5

Others: live in missionary, prison

Clinical characteristics of respondents

Table 2 shows the distribution of clinical characteristics of the respondent. It was observed from the table that more than one-third of participants (42.2%) had a clinical diagnosis of schizophrenia, followed by major depressive disorder (33.7%). The mean (±) age at onset of the illness was 29.1 (±9.6) years, with age at onset ranging from 16 years to 59 years. More than one-third (45.8%) of participants had a total illness duration of less than 5 years, and 37.7% of them had an untreated illness duration of less than 2 years. More than three-fourths (78.3%) of respondents had a history of traditional treatment; most of them (43.5%) went to Sheka House (Ruqiya) for help. 5.1% of respondents had a history of chronic medical illness, and half (50.6%) of study participants had a history of relapse. Nearly half (48.5%) of the participants had a history of admission, while more than half (58.1%) had not experienced side effects from the medications. 39.8% of them were currently being treated with antipsychotic monotherapy. About 6.6% of participants had a history of suicidal attempts in the past year, and more than half (56%) of the respondents adhered to the psychotropic medications.

Table 2. Clinical characteristics of patients with severe mental illness attending public hospitals in Harar town, Eastern Ethiopia, 2023 (n=332).

Variables	Category	Frequency (n)	Percentage (%)
Clinical diagnosis	Schizophrenia	140	42.2
	Major depressive disorder	112	33.7
	Bipolar disorder	80	24.1
Age at illness onset	Mean=29.1 SD = ±9.6
Duration of the illness	<5 years	152	45.8
	5–10 years	115	34.6
	>10 years	65	19.6
Duration of untreated illness	<2 years	125	37.7
	2–5 years	120	36.1
	>5 years	87	26.2
Traditional treatment	Yes	260	78.3
	No	72	21.7
Types of traditional treatment	Holy water	87	32.6
	Sheka House (Ruqiya)	116	43.5
	Praying	31	11.6
	Wizard/witch	19	7.1
	Herbal medicine	14	5.2
Number of relapses	None	164	49.4
	01/02/25	105	31.6
	>2	63	19
History of hospitalisation	None	171	51.5
	≤2	110	33.1
	>2	51	15.4
Types of medication	Antipsychotic	132	39.8
	AD	57	17.2
	MS	31	9.3
	Antipsychotic with AD	63	18.9
	Antipsychotic with MS	49	14.8
Medication adherence	Adherent	186	56
	Non-adherent	146	44
Medication side effect	Yes	139	41.9
	No	193	58.1
Suicidal attempt	Yes	22	6.6
	No	310	93.4
Chronic illness	Yes	17	5.1
	No	315	94.9
Types of chronic illness	Hypertension	10	58.8
	Diabetes mellitus	3	17.6
	Epilepsy	2	11.8
	HIV/AIDS	2	11.8

AD, antidepressant; MS, mood stabiliser.

Psychosocial and substance use characteristics of respondents

Regarding social support, 42.8% of respondents had moderate social support. Regarding perceived stigma, 53.6% of participants reported higher perceived stigma. In terms of substance use, 66.6% of respondents have used Khat in their lifetime, with 61.5% currently chewing Khat. Additionally, 46.1% of respondents had a history of smoking tobacco, and the majority (68.4%) had no history of alcohol use (table 3).

Table 3. Psychosocial and substance use characteristics of patients with severe mental illness attending care at public hospitals in Harar town, Eastern Ethiopia, 2023 (n=332).

Variables	Category	Frequency (n)	Percentage (%)
Social support	Poor	100	30.1
	Moderate	142	42.8
	High	90	27.1
Perceived stigma	High	178	53.6
	Low	154	46.4
Lifetime alcohol use	Yes	105	31.6
	No	227	68.4
Lifetime tobacco use	Yes	153	46.1
	No	179	53.9
Lifetime khat use	Yes	221	66.57
	No	111	33.43
Current alcohol use	Yes	51	15.4
	No	281	84.6
Current tobacco use	Yes	59	17.8
	No	273	82.2
Current khat use	Yes	204	61.45
	No	128	38.55

Functional disability status of study participants

In this study, the overall mean score of functional disability among patients with SMI was 31.8 (95% CI: 30.7 to 32.8) with a SD of 9.6. The minimum and maximum scores of the study participants on the Functional Disability Scale were 14 and 49, respectively.

Factors associated with functional disability

A simple linear regression analysis was carried out between functional disability and each independent variable. Variables with a p value<0.2 during simple linear regression analysis were selected for further analysis in multiple linear regression analysis. In a simple linear regression analysis, living arrangement, job status, total illness duration, age at onset of illness, number of relapses, history of hospitalisation, drug side effects, current khat use, medication non-adherence and perceived stigma were significantly associated with functional disability.

In multiple linear regression analysis, job status, total illness duration, age at onset of illness, drug side effects, medication adherence and perceived stigma were significantly associated with functional disability.

As table 4 shows the results of the statistical analysis conducted on the data, being unemployed increases the functional disability score by 1.93 units (β: 1.93, 95% CI: 0.28 to 3.59). The functional disability score decreases by 0.37 for every unit increase in age at onset of the illness (β: −0.37, 95% CI: −0.45 to −0.28). In terms of total illness duration, respondents with 5–10 years of illness had a 3.71-unit increase in functional disability scores (β: 3.71, 95% CI: 1.95 to 5.48), whereas those with more than 10 years of illness had a 4.51-unit increase in functional disability scores (β: 4.51, 95% CI: 2.41 to 6.62).

Table 4. Multivariate linear regression for assessment of functional disability and associated factors among people with severe mental illness attending care at public hospitals in Harar town, Eastern Ethiopia, 2023 (n=332).

Variables	Categories	SLR – β: (95% CI)	MLR – β: (95% CI)
Job status	Unemployed (Ref employed)	3.87 (1.68 to 6.06)	1.93 (0.28 to 3.59)**
Living arrangement	Alone Others (Ref with family)	4.76 (2.2 to 7.32) −1.20 (−6.13 to 3.72)	1.27 (-0.97 to 3.24) 1.91 (−2.78 to 5.40)
Duration of illness (In years)	5–10 >10 (Ref<5)	4.87 (2.67 to 7.09) 7.90 (5.25 to 10.55)	3.71 (1.95 to 5.48)*** 4.51 (2.41 to 6.62)***
Age at illness onset		−0.48 (−0.57 to −0.38)	−0.37 (−0.45 to −0.28)**
Untreated illness duration (In years)	2–5 >5 (Ref<2)	2.34 (−0.037 to 4.72) 4.26 (1.66 to 6.86)	0.90 (−0.89 to 2.70) 0.56 (−1.42 to 2.55)
Number of relapses	1–2 >2 (Ref none)	2.15 (−0.19 to 4.51) 2.19 (−0.60 to 4.98)	1.24 (−0.49 to 2.98) 1.45 (−0.62 to 3.53)
History of hospitalisation	≤2 >2 (Ref none)	1.18 (−1.12 to 3.49) 2.19 (−0.81 to 5.20)	1.07 (−0.65 to 2.79) 1.93 (−0.39 to 4.25)
Drug side effect	Yes (Ref no)	6.1 (4.10 to 8.09)	3.05 (1.46 to 4.63)***
Recent khat use	Yes (Ref no)	4.64 (2.5 to 6.8)	1.20 (−0.42 to 2.83)
Medication adherence	Non-adherent (Ref adherent)	9.32 (7.49 to 11.15)	6.15 (4.56 to 7.73)***
Perceived stigma	High (Ref low)	4.82 (2.81 to 6.84)	2.27 (0.72 to 3.82)**

R2=0.501, AR2=0.476; *p<0.05, **p<0.01, ***p<0.001.

MLR, multiple linear regression; SLR, simple linear regression; β, Unstandardized beta coefficient.

Those patients with SMIs who had a history of medication side effects had a 3.05-unit increase in their functional disability score (β: 3.05, 95% CI: 1.46 to 4.63). Non-adherence to psychiatric medication increased the functional disability score by 6.15 units (β: 6.15, 95% CI: 4.56 to 7.73). A unit increase in perceived stigma scores increases functional disability by 2.27 units (β: 2.27, 95% CI: 0.72 to 3.82).

Discussion

Functional disability is a common negative consequence of mental illness that affects patients’ cognitive, interpersonal and motor functions. It has a negative impact on daily living since it makes it harder for patients to carry out their daily tasks in multiple domains.³⁷

This study revealed that the overall mean score of functional disability among patients with SMI was 31.8 (±9.6).

The result of the present study is in line with studies done in Addis Ababa, Ethiopia; the overall mean score of functional disability was 30.3.¹⁹ However, our study’s mean functional disability score was higher than studies conducted in Butajira (mean score of 22.3),²⁶ Jimma (mean score of 11.1),⁴ Sudan (mean score of 25.6)¹⁵ and Lagos, Nigeria (mean score of 27.02).¹⁴ The possible reasons could be the differences in sample size, clinical characteristics of study participants and the study setting. The sample size in the Butajira study was smaller than the current study, which can underestimate the finding. In Jimma’s study, the target group was all individuals with mental illness, and the study setting was a community. Since this study focused on patients with SMI in which functionality could be likely affected when compared with other mental disorders. In contrast to the current study, which was conducted in Sudan, the study target group consisted solely of patients suffering from bipolar disorder, and in Lagos, Nigeria, the participants were patients suffering from bipolar disorder and schizophrenia, in which discrepancies are attributed to different target populations.

The current study’s findings were also higher than those of previous studies conducted in six European countries (mean score of 8.7),³⁸ Barcelona (mean score of 18.68),³⁹ New Delhi, India (mean score of 5.1),¹⁶ Kerala, India (mean score of 19.2)⁴⁰ and China (mean score of 7.89).¹³

The discrepancies might be due to differences in socioeconomic and cultural characteristics, measurement tools, sample size, target population, study setting and participant selection.

Participants in the European study were drawn from a general population sample with no history of mental healthcare visits, and only people with mood and anxiety disorders were included. The sample size in the Barcelona and both Indian studies was lower than the current study, and it included only patients with a diagnosis of bipolar disorder. In the latter study, an additional reason could be the use of a different measurement tool, which was the Indian Disability and Evaluation Scale. Unlike WHODAS, this tool had no specific duration to assess the level of functionality. In the Chinese study, patients with a history of long hospitalisation were recruited.

Furthermore, in developed nations, advanced knowledge of mental illnesses and better mental healthcare delivery systems account for lower functional disability among people with SMIs. On the contrary, the findings of our study were lower than those of studies conducted in Benin City, Nigeria (mean score of 69.13)⁹ and Inner Mongolia, China (mean score of 66.19).⁴¹

The difference could be related to measurement tool differences, with WHODAS being used to assess the functional status of current study participants, whereas the Global Functional Assessment Tool (GAF) was used in the Benin City, Nigeria, study, which is more subjective than WHODAS, as well as variation in sampling due to the purposive sampling technique, which can increase the estimate of functional disability.

In this study, factors such as job status, illness duration, age at illness onset, drug side effects, medication non-adherence and perceived stigma were significantly associated with functional disability.

Being unemployed increases the functional disability score by 1.93 units. This relationship could be justified as, through stress and reduced self-esteem arising from the loss of the day-to-day structure of work, stigma associated with unemployment results in financial hardship, insecurity and reduced future earnings potential, which have a detrimental effect on the overall functional status of patients with SMI.⁴² A recent study in rural Ethiopia also revealed that more than half of patients with SMI had work impairment due to several factors.⁴³ This finding is supported by studies conducted in north-west Ethiopia¹² and Nigeria.¹⁴ The functional disability score decreases by 0.37 for every unit increase in age at the onset of the illness. This association could be explained by the fact that a diagnosis of SMI at a younger age is associated with a longer duration of illness, poorer clinical and functional outcomes and a longer term of psychiatric care.⁴⁴ This finding is also in agreement with studies conducted in Thailand.⁴⁵

Respondents whose illness duration was 5–10 years showed a 3.71-unit increase in functional disability scores, whereas those whose illness duration was above ten years increased their functional disability score by 4.51 units. This is also explained by the fact that a longer total duration of illness has been linked with poorer remission status, more severe symptoms, more disability in overall functioning and a lower overall quality of life.⁴⁶ Studies from Northwestern Ethiopia¹² and India⁴⁷ had similar findings.

Those patients with SMI who had a history of medication side effects showed a 3.05-unit increase in functional disability score. Medication side effects interfered with patients' normal functioning and had a significant impact on non-adherence.⁴⁸ This finding is supported by studies conducted in Butajira.²⁶ Patients who were non-adherent to psychotropic medications were found to have a 6.15-unit increase in functional disability score when compared with their counterparts. This is corroborated by the fact that non-adherence has a significant impact on illness progression, complications, reduced treatment effectiveness or decreased responsiveness to subsequent treatment, relapse, hospitalisations, increased suicide and poor quality of life, all of which may result in greater disability in overall functioning.⁴⁹ This finding is in agreement with studies conducted in China⁴¹ and Egypt.¹⁷ A unit increase in perceived stigma scores increases functional disability by 2.27 units. This can be explained by the fact that stigma worsens symptoms, lowers the likelihood that a person will seek treatment and makes it less likely that they will complete therapy, all of which have a detrimental impact on recovery and functional restoration in people with serious mental illnesses.⁵⁰ This finding is in line with studies conducted in Jimma,⁴ Addis Ababa¹⁹ and Sudan.¹⁵

Strengths and limitations of the study

A multicentre study was carried out to ensure the representativeness and generalisability of the findings. A valid data collection tool, the WHODAS, which has a high internal consistency, was used.

This study also has some flaws, including social desirability bias due to the interviewer-administered data collection method. The study’s cross-sectional nature prevented it from accurately capturing the cause-and-effect relationship of the outcome variable.

Conclusions

The mean functional disability score among the respondents was high. Functional disability was significantly associated with characteristics such as unemployment, age at onset of mental illness, length of illness, medication side effects, non-adherence and higher perceived stigma. Given the mean functional disability score observed among respondents, a multipronged intervention strategy that prioritises early detection and management of SMI, particularly targeting individuals at risk, is recommended to mitigate disability and enhance quality of life. Clinical management should emphasise minimising medication side effects through personalised pharmacotherapy and regular monitoring while also implementing adherence-enhancing strategies. Additionally, stigma reduction initiatives are critical in decreasing perceived stigma and promoting sustained functional recovery.

Data availability statement

Data are available upon reasonable request.