Caregiving burden, depression, and anxiety in informal caregivers of people with mental illness in China: a cross-sectional survey

Abstract

Background

Caregiving for people with mental illness (PwMI) could be burdensome, especially for informal caregivers. However, there is a scarcity of research investigating caregiving burden among informal caregivers of PwMI in China at the national level. To fill this gap, this study examined the prevalence of caregiving burden, depression, and anxiety, as well as their associated factors, among a cross-sectional sample of informal caregivers of PwMI in China.

Methods

Data were collected via an online survey between June and November 2023. Caregiving burden, depression, and anxiety were measured by the Zarit Burden Interview, the Patient Health Questionnaire, and the Generalized Anxiety Disorder Scale. Information on caregivers’ sociodemographic, care recipients’ sociodemographic and disease-related, and caregiving-related characteristics was also collected. Hierarchical regression analyses were performed to identify associated factors of caregiving burden, depression, and anxiety.

Results

A total of 1,224 informal caregivers of PwMI in China were included in the final analysis. 72.1% of the participants had high caregiving burden, 53.5% had moderate to severe depression, and 43.1% had moderate to severe anxiety. Caregiving burden, depression, and anxiety were inter-correlated with each other but exhibited different profiles of associated factors. The most important factors associated with all the three outcomes were disease-related characteristics, particularly care recipients’ symptom stability, medication compliance, and insight. Informal caregivers of males with mental illness had higher levels of caregiving burden, depression, and anxiety than those of females. There was a lack of differentiation in caregiving burden, depression, and anxiety based on care recipients’ diagnosis. Formal or common-law marriage was a protective factor for caregiver depression and anxiety but not for caregiving burden.

Conclusion

Informal caregivers of PwMI in China experienced a high level of caregiving burden, depression, and anxiety. Urgent actions are needed to relieve caregiving burden, depression, and anxiety among informal caregivers of PwMI in China.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12888-024-06239-4.

Introduction

Caregiving for people with mental illness (PwMI) could be burdensome, especially for informal caregivers. According to Roth et al. [1], an informal caregiver was defined as “a person who provides some type of unpaid, ongoing assistance with activities of daily living or instrumental activities of daily living to a person with a chronic illness or disability”. Most often, it is family members who hold the main responsibility for providing informal caregiving for PwMI, given that a considerable percentage of PwMI around the world are living with their families, while friends, neighbors, and others could also play a significant, if not primary, role in such caregiving. Unlike formal caregivers (e.g., psychiatrists, nurses, social workers, and other mental health professionals) who only provide temporary or intermittent care for PwMI, informal caregivers often serve as their long-term, and possibly even life-long, companions, participating in a multitude of trivial, frequent, and seemingly endless caregiving tasks for them, such as supervising medication intake, taking them to medical appointments, providing financial support, offering daily life care, and comforting them when they experience emotional or behavioral disturbances. More importantly, it is informal caregivers who accompany individuals with mental illness through their journey to recovery, sharing with them the lived experiences of struggles and successes, setbacks and progresses, and losses and gains on that journey, not for a while, but for a time of unspecified length. Such trivialities and uncertainties entailed in informal caregiving can, however, impose significant stress on caregivers, bringing about detrimental impacts on their health and wellbeing.

Previous studies have documented an array of negative consequences induced by caregiving among informal caregivers of people with different diagnoses of mental illness, such as schizophrenia [2], bipolar disorder [3], and intellectual and developmental disorder [4]. One of the most researched negative consequences of informal caregiving is caregiving burden, which can be defined as “the extent to which caregivers perceived their emotional, physical health, social life, and financial status as a result of caring for their relative” [5]. According to one meta-analysis published in 2022 which included 39 studies from 23 countries, the overall pooled prevalence of caregiving burden among caregivers of PwMI was 31.67% (95% CI 26.22–37.12) [6]. Moreover, a high level of caregiving burden, if left unresolved, can lead to increased risks of mental ill-health, including depression and anxiety, among informal caregivers of PwMI [7–9], eroding the quality of care provided by them and eventually compromising the care recipients’recovery and rehabilitation.

Literature has shown that caregiving burden is influenced by a variety of factors. According to Pearlin’s stress-process model [10], there are three domains of factors associated with caregiving burden: (a) the background factors; (b) the stressors; and (c) the mediators. Background factors encompass the sociodemographic characteristics of both the caregiver and the care recipient (e.g., age, gender, ethnicity, education, employment, and economic status), as well as caregiving-related characteristics (e.g., the caregiver’s relationship to the care recipient and the duration of caregiving). Stressors are divided into those that are primary and secondary. Primary stressors include the care recipient’s disease-related characteristics (e.g., symptomology and functional status) and the subjective challenges experienced by the caregiver. Secondary stressors refer to role strains and intrapsychic strains faced by the caregiver. Additionally, mediators such as coping and social support play a crucial role in buffering the effects of stressors on caregiving burden. One seminal review reported that overall burden among caregivers of PwMI was positively associated with ethnicity, symptomatic behaviors, and amount of care provided [11]. Another review indicated a significant association between caregiving burden and the care recipient’s disease-related characteristics, including symptomology, functional status, and duration of illness, among informal caregivers of people with schizophrenia [12]. However, the associations between caregiving burden and the caregiver’s and the care recipient’s sociodemographic characteristics are mixed [11]. The effect of the care recipient’s diagnosis on caregiving burden is also unclear [13].

Due to rapid social changes, China has witnessed a dramatic increase in cases of mental illness in the last three decades. Findings from the Global Burden of Disease Study 2019 showed that, in China, from 1990 to 2019, the number of incident cases due to mental illness increased by 22.9%, the number of prevalent cases increased by 20.8%, and the number of disability-adjusted life years increased by 29.7% [14]. Based on the prevalence estimates from the China Mental Health Survey, there are approximately 130 million individuals with any mental illness (excluding dementia) in China nowadays [15], accounting for 13.4% of global prevalent cases [14]. Such a large number of individuals with mental illness potentially means an equally large number of informal caregivers for them in China, although the specific number is currently lacking and urgently needs estimation.

Different from many Western countries where de-institutionalization has, to a large extent, changed the scenario of caregiving for PwMI by shifting the burden of care for PwMI from psychiatric hospitals to families and social support networks, China has not undergone such a process of mass closures of psychiatric hospitals. Instead, large psychiatric hospitals are still playing an irreplaceable role, at least for the foreseeable future, in formal care for PwMI in China. Despite these formal care options provided by hospitals, it is worth noting that a significant share of burden of care for PwMI is still being shouldered by their informal caregivers due to several specific socioeconomic and cultural factors. First, the deeply rooted values of traditional familism and Confucian ethics in China’s society place upon people a moral obligation, even if unwanted sometimes, to provide care for family members who fall ill. Second, the Chinese government has further institutionalized care for PwMI as a legal duty of family members by legislation. As Article 21 of China’s Mental Health Law stipulates, “if it appears that a family member may have a mental disorder, other family members shall help them obtain prompt medical care, provide for their daily needs, and assume responsibility for their supervision and management.” [16]. In addition, under China’s civil law system, if individuals with mental illness are declared to have no or limited capacity for civil conduct, the family members shall act as their guardians, representing them in the performance of civil juridical acts. Third, in the context of severe mental illness, the Chinese government also includes guardians of people with SMI as an important component of its Severe Mental Illness Management System, famously known as the “686 System” [17], and, in recent years, has implemented a reward and subsidy policy for guardians to ensure they assume their guardianship responsibilities [18]. The responsibilities include, among others, protecting the basic rights of the person with SMI, ensuring their medication, caring for their daily life, helping them seek timely medical attention when their condition fluctuates, providing reasonable supervision to prevent them from endangering others’lives and property, and, if necessary, arranging for involuntary hospitalization. Fourth, from a more realistic view, the existing resources of formal care for PwMI are far from sufficient in China, and most of them are concentrated in the more urbanized Eastern coastal region of China [19]. Community-based mental health care and support is scarce. Still a lot of PwMI in China, especially those living in rural areas and in Central and Western regions of China, have no or limited access to quality formal care and thus rely heavily on informal care provided by their family members and wider social support networks. Last, despite the many responsibilities placed upon informal caregivers of PwMI in China, their needs have long been overlooked by China’s mental health system and society at large [20, 21]. To this day, there is very little support, whether in the form of respite care, psychological counselling, skills training, care leave, or more flexible work arrangements, available to informal caregivers of PwMI in China. Also, at the policy level, the unique contributions made by informal caregivers to the provision of care for PwMI have not been fully acknowledged.

In summary, all the above-mentioned socioeconomic and cultural factors have created a caregiving reality for informal caregivers of PwMI in China that may differ from that in other countries and possibly exposed these caregivers to a higher risk of caregiving burden and its mental health ramifications. However, there is still a scarcity of research investigating caregiving burden among informal caregivers of PwMI in China. The few existing studies either focused on a specific diagnosis of mental illness or restricted their scope of investigation to a particular city or district [22, 23]. The overall prevalence of caregiving burden and its mental health ramifications, such as depression and anxiety, among informal caregivers of PwMI in China remains unknown. The impact of various caregiver-related, care recipient-related, and caregiving-related factors on caregiving burden also warrants further exploration. To fill this gap, the current study conducted a cross-sectional survey on caregiving burden, depression, and anxiety among informal caregivers of PwMI in China. To be more specific, this study focuses on three main objectives: (1) to examine the prevalence of caregiving burden, depression, and anxiety among informal caregivers of people with mental illness in China, (2) to investigate the inter-correlations between caregiving burden, depression, and anxiety, and (3) to identify the respective profiles of associated factors of caregiving burden, depression, and anxiety. In this study, we primarily surveyed four categories of basic information related to caregiver-care recipient dyads, that is (a) caregivers’ sociodemographic characteristics, (b) care recipients’ sociodemographic characteristics, (c) care recipients’ disease-related characteristics, and (d) caregiving-related characteristics, and examined their effects on caregiving burden, depression, and anxiety among caregivers. According to Pearlin’s stress-process model [10], the category of care recipients’ disease-related characteristics falls under the primary stressors of caregiving burden, while the other three categories pertain to the background of caregiving burden.

Methods

Study design

This study adopted a descriptive, cross-sectional design using data collected from an online survey.

Participants and procedure

Those who identified themselves as an informal caregiver of a person with a diagnosis of mental illness in China were invited to participate in this study. In this study, the informal caregiver could be the relative, partner, neighbor, friend, or anyone else who has a significant personal relationship with, and provides informal caregiving for, the care recipient. This study also did not limit the participants to the primary caregivers or those who reside with the care recipients. Other inclusion criteria of the participants included: (1) not being younger than 18 years old; (2) having already provided more than three months of informal caregiving for the care recipient; and (3) being able to read and fill in the questionnaire themselves. According to the rule of thumb, the sample size large enough for sufficient power to detecting associations in regression models should be at least 10 participants per independent variable [24]. In this study, 49 independent variables were included in the final regression model (see Supplementary Table 7). So, the sample size should be at least 490 participants.

Participants were recruited through an online questionnaire using “Questionnaire Star”, a popular online survey tool in China. The questionnaire was distributed across a variety of social media platforms in China, including WeChat, Douban, Weibo, and QQ, all of which were among the most popular social media platforms in China. The informed consent form was presented on the first page of the questionnaire and only those who checked the consent box on the form were guided to complete the remaining part of the questionnaire. About 15–20 min were needed to complete the questionnaire. All questionnaires were collected between June 2023 and November 2023. Ethical approval of the study was obtained from the Ethics Committee of Shanghai Mental Health Center, Shanghai Jiao Tong University (Reference Number: 2023–74).

Instruments

Basic information

Four categories of basic information related to caregiver-care recipient dyads were surveyed in this study, that is (a) caregivers’ sociodemographic characteristics, (b) care recipients’sociodemographic characteristics, (c) care recipients’disease-related characteristics, and (d) caregiving-related characteristics. In addition, the regional distribution of caregivers that participated in this study was examined by asking about their place of residence.

Caregivers’ sociodemographic characteristics: including caregivers’ gender (male; female), age, education (primary school or below; secondary school; associate degree; bachelor’s degree; master’s degree or above), marital status (never married; married or living common-law; divorced or separated; widowed), employment (full-time; part-time; unemployed; student; retired), and household annual income (≤ 50,000 RMB; 50,000–100,000 RMB; 100,000–200,000 RMB; 200,000–40,000 RMB; > 400,000 RMB).

Care recipients’ sociodemographic characteristics: including care recipients’ gender (male; female), age, education (primary school or below; secondary school; associate degree; bachelor’s degree; master’s degree or above), marital status (never married; married or living common-law; divorced or separated; widowed), and employment (full-time; part-time; unemployed; student; retired).

Care recipients’ disease-related characteristics: including care recipients’ diagnosis, illness duration, comorbidity of chronic physical illness, symptom stability, medication compliance, and insight. Care recipients’ comorbidity of chronic physical illness was measured by asking the caregiver whether the care recipient was suffering from any chronic physical illness. Care recipients’ symptom stability was measured on a 5-point Likert scale by asking the caregiver whether he/she thought the care recipient’s symptoms had been stable over the past month (1 = very unstable; 2 = unstable; 3 = neutral; 4 = stable; 5 = very stable). Care recipients’ medication compliance was also measured on a 5-point Likert scale by asking the caregiver whether he/she thought the care recipient had been compliant with the medications over the past month (1 = very non-compliant; 2 = non-compliant; 3 = neutral; 4 = compliant; 5 = very compliant). Care recipients’ insight was measured based on three caregiver-rated items regarding whether the care recipient is aware of his/her illness symptoms, need for treatment, and consequences of illness [25]. The three items were scored on a 3-point scale (0 = not aware at all; 1 = partially aware; 2 = clearly aware). The sum score of the three items (ranging from 0 to 6) was calculated as the measure of care recipients’ insight, with a higher score indicating a higher level of insight. In the present study, the Cronbach’s alpha for the three items was 0.900.

Caregiving-related characteristics: including caregivers’ relationship with the care recipient (parent; child; spouse; sibling; relative other than the parent, child, spouse, or sibling; others), duration of caregiving, whether the caregiver was the primary caregiver of the care recipient, whether there was any other caregiver assisting with the caregiving for the care recipient, and whether there was any other care recipient that the caregiver had to provide care for.

12-item Zarit Burden Interview (ZBI-12)

Caregiving burden was measured using the ZBI [5], one of the most commonly used instrument for assessing caregiving burden of a variety of illnesses including mental illness [26–28]. The Chinese version of ZBI has been widely used in China as a validated measurement of caregiving burden [29]. The full ZBI form (i.e., ZBI-22) consists of 22 items. In addition, several short forms of ZBI have since been developed for the facilitation of rapid assessment of caregiving burden as well as for the alleviation of respondent burden of caregivers who have been already heavily burdened with their caregiving activities. This study utilized the 12-item version of ZBI (ZBI-12) proposed by Bédard et al. [30] which has shown the best performance in psychometric testing compared with other short forms of ZBI [31–33]. The Bédard ZBI-12 is scored on a 5-point Likert scale with a larger sum score (ranging from 0 to 48) indicating a higher level of burden. Currently, there is no universally accepted cutoff value for the Bédard ZBI-12 used in informal caregivers of PwMI. Bédard et al. [30] themselves proposed 17 as a potential cutoff value for differentiating low and high levels of caregiving burden, which was also used in this study. The Chinese version of Bédard ZBI-12 has also been shown to have sound validity and reliability among informal caregivers in China [34, 35]. In the current study, the Cronbach’s alpha for the Chinese version of Bédard ZBI-12 was 0.933.

9-item Patient Health Questionnaire (PHQ-9)

The PHQ-9 [36] was used to measure caregivers’ depressive symptoms and consists of 9 items scored on a 4-point Likert scale from 0 (not at all) to 3 (nearly every day). The sum score ranges from 0 to 27, with a larger sum score indicating a higher level of depression. According to the sum score on the PHQ-9, the participants were further categorized into those with minimal depression (sum score 0–4), those with mild depression (sum score 5–9), those with moderate depression (sum score 10–14), those with moderately severe depression (sum score 15–19), and those with severe depression (sum score 20–27). The Chinese version of PHQ-9 has been widely used in China to measure depression among different populations and demonstrates sound validity and reliability [37–39]. In the present study, the Cronbach’s alpha for the Chinese version of PHQ-9 was 0.929.

7-item Generalized Anxiety Disorder Scale (GAD-7)

The GAD-7 [40] was used to measure caregivers’ anxiety and consists of 7 items scored on a 4-point Likert scale from 0 (not at all) to 3 (nearly every day). The sum score ranges from 0 to 21, with a larger sum score indicating a higher level of anxiety. According to the sum score on the GAD-7, the participants were further categorized into those with minimal anxiety (sum score 0–4), those with mild anxiety (sum score 5–9), those with moderate anxiety (sum score 10–14), and those with severe anxiety (sum score 15–21). The GAD-7 has been translated into Chinese and shows sound psychometric properties among Chinese populations [41–43]. In the present study, the Chinese version of GAD-7 demonstrated good internal consistency (Cronbach’s alpha = 0.940).

Data analysis

All statistical analyses were conducted using the SPSS software version 29.0 (Chicago, IL, USA). Continuous variables are presented as means and standard deviations (SD) or medians and interquartile ranges (IQR) as appropriate, and categorical variables as counts and percentages. The participants’ places of residence were consolidated into four major economic regions of China, that is north-eastern, eastern, middle, and western region. Student’s t-tests and ANOVA tests were used to identify the between-group differences on caregiving burden, depression, and anxiety for categorical characteristics. Univariate regression analyses were conducted to identify the effects of continuous characteristics on caregiving burden, depression, and anxiety, as well as the inter-correlations between caregiving burden, depression, and anxiety. In addition to univariate regression analyses, the inter-correlations between caregiving burden, depression, and anxiety were also tested through multiple regression analyses with all the variables in the four categories of basic information related to caregiver-care recipient dyads included as potential confounding variables. In order to understand how each category of characteristics contributed to the explanation of variance in caregiving burden, depression, and anxiety, hierarchical regression analyses were performed. One strength of hierarchical regression analysis was that it could help elucidate the incremental value of each category of characteristics in determining caregiving burden, depression, and anxiety among informal caregivers of PwMI in China. Four blocks representing caregivers’ sociodemographic, care recipients’ sociodemographic, disease-related, and caregiving-related characteristics were sequentially included in the regression models. All the characteristics in the four categories were used. Multicollinearity was checked for each characteristic through the values of tolerance (less than 0.10) and variance inflation factor (greater than 10) before running hierarchical regression analyses and no characteristic was detected with a high level of multicollinearity (see Supplementary Table 6 for the results of multicollinearity analysis). R-square changes were calculated to show how much additional variance was explained by each category of characteristics in the regression models, with F-tests conducted to examine whether the newly added category of characteristics significantly improved the models. All statistical tests were two-tailed, with p < 0.05 considered statistically significant.

Results

Description of caregivers’ sociodemographic, care recipients’ sociodemographic, disease-related, and caregiving-related characteristics

A total of 1,500 responses were collected, of which 1,224 (79.0%) were valid and used in the final analysis. Table 1 shows the basic information on caregivers’ sociodemographic, care recipients’ sociodemographic, disease-related, and caregiving-related characteristics, as well as the regional distribution of caregivers that participated in this study. The caregivers’ median age was 47 years, with females comprising the vast majority (80.2%). Two thirds of the caregivers were married or living common-law. Close to half of the caregivers were employed full-time or part-time. The care recipients’ median age was 28 years. Half of the care recipients were female. The majority (70.0%) of the care recipients were unmarried. Close to half of the care recipients were unemployed. The four most common mental illnesses among the care recipients were schizophrenia (31.5%), bipolar disorder (25.5%), autism spectrum disorder (14.9%), and depressive disorder (8.6%). The median duration of illness was 10 years. The care recipients’ mean scores for symptom stability, medication compliance, and insight rated by the caregivers were 3.15 (SD 1.11), 3.61 (SD 1.17), and 3.20 (SD 2.11) respectively. With regard to the caregiving relationship, 57.6% of the caregivers were parents, 12.5% were children, 12.0% were spouses, and 5.8% were siblings. The median duration of caregiving for the care recipients was 6 years. Most caregivers were the primary caregivers for their care recipients. Over half of the caregivers needed to care for someone else besides the person with mental illness. Two thirds of the caregivers did not have someone else assisting with caregiving for the person with mental illness. The caregivers that participated in this study were distributed in 31 province-level administrative divisions of China, with the eastern region of China contributing the largest proportion of participants (57.84%) (see Supplementary Table 1 for more details).

Table 1.

Description of caregivers’ sociodemographic, care recipients’ sociodemographic, disease-related, and caregiving-related characteristics

Characteristics	N (%), median (IQR), or mean (SD)
CG sociodemographic characteristics
CG gender, N (%)
Male	242 (19.8)
Female	982 (80.2)
CG age (years), median (IQR)	47 (35, 54)
CG education, N (%)
Primary school or below	40 (3.3)
Secondary school	297 (24.3)
Associate degree	301 (24.6)
Bachelor’s degree	459 (37.5)
Master’s degree or above	127 (10.3)
CG marital status, N (%)
Never married	231 (18.9)
Married or living common-law	823 (67.2)
Divorced or separated	125 (10.2)
Widowed	45 (3.7)
CG employment, N (%)
Full-time	476 (38.9)
Part-time	110 (9.0)
Unemployed	256 (21.0)
Student	93 (7.6)
Retired	289 (23.6)
CG household annual income (RMB), N (%)
≤ 50,000	302 (25.6)
50,000–100,000	342 (29.0)
100,000–200,000	310 (26.3)
200,000–40,000	137 (11.6)
>400,000	88 (7.5)
CR sociodemographic characteristics
CR gender, N (%)
Male	572 (46.7)
Female	652 (53.3)
CR age (years), median (IQR)	28 (19, 42)
CR education, N (%)
Primary school or below	270 (22.1)
Secondary school	228 (18.6)
Associate degree	237 (19.4)
Bachelor’s degree	172 (14.1)
Master’s degree or above	317 (25.9)
CR marital status, N (%)
Never married	857 (70.0)
Married or living common-law	257 (21.0)
Divorced or separated	70 (5.8)
Widowed	40 (3.3)
CR employment, N (%)
Full-time	130 (10.6)
Part-time	40 (3.3)
Unemployed	572 (46.8)
Student	353 (28.8)
Retired	129 (10.5)
Disease-related characteristics
CR diagnosis, N (%)
Schizophrenia	386 (31.5)
Bipolar disorder	312 (25.5)
Depressive disorder	105 (8.6)
Autism	182 (14.9)
Others	239 (19.5)
CR illness duration (years), median (IQR)	10 (5, 18)
CR comorbidity of chronic physical illness, N (%)	496 (40.5)
CR symptom stability, mean (SD)	3.15 (1.11)
CR medication compliance, mean (SD)	3.61 (1.17)
CR insight, mean (SD)	3.20 (2.11)
Caregiving-related characteristics
Relationship with the CR, N (%)
Parent	705 (57.6)
Child	153 (12.5)
Spouse	147 (12.0)
Sibling	71 (5.8)
Relative other than parent, child, spouse, or sibling	70 (5.7)
Others	78 (6.4)
Duration of caregiving for the CR (years), median (IQR)	6 (3, 13)
Co-residence with the CR, N (%)	1011 (82.6)
Being the primary CG, N (%)	1038 (84.8)
Presence of other CG, N (%)	681 (55.6)
Presence of other CR, N (%)	426 (34.8)
Regional distribution of participants
North-eastern region of China, N (%)	48 (3.9)
Eastern region of China, N (%)	708 (57.8)
Middle region of China, N (%)	203 (16.6)
Western region of China, N (%)	265 (21.7)

Abbreviations: CG caregiver, CR care recipient, RMB Renminbi

Caregiving burden, depression, and anxiety among caregivers

Table 2 presents the caregivers’ levels of caregiving burden, depression, and anxiety. For caregiving burden, the caregivers had an average score of 25.51 (SD 12.44) on the ZBI-12, with 72.1% experiencing high burden. For depression, the caregivers had an average score of 11.59 (SD 6.85) on the PHQ-9, with 53.5% experiencing moderate to severe depression. For anxiety, the caregivers had an average score of 9.25 (SD 5.92) on the GAD-7, with 43.1% experiencing moderate to severe anxiety. Univariate regression analyses indicated significant inter-correlations between caregiving burden, depression, and anxiety among caregivers (Table 3). After adjusting for all the variable in the four categories of basic information related to caregiver-care recipient dyads, caregiving burden, depression, and anxiety among caregivers were still significantly inter-correlated. After adjustment, the ZBI-12 score increased by 0.983 points for each 1-point increase in PHQ-9 score (SE = 0.041, β = 0.540, t = 23.786, p < 0.001) and by 1.190 points for each 1-point increase in the GAD-7 score (SE = 0.045, β = 0.567, t = 26.439, p < 0.001). Additionally, after adjustment, the PHQ-9 score increased by 0.917 points for each 1-point increase in the GAD-7 score (SE = 0.020, β = 0.795, t = 46.600, p < 0.001).

Table 2.

Caregiving burden, depression, and anxiety in informal caregivers of people with mental illness

Scale	Score, mean (SD)	Level of severity	N (%)
ZBI-12	25.51 (12.44)	Low	341 (27.9)
		High	883 (72.1)
PHQ-9	11.59 (6.85)	None to minimal	191 (15.6)
		Mild	374 (30.6)
		Moderate	260 (21.2)
		Moderately severe	215 (17.6)
		Severe	184 (15.0)
GAD-7	9.24 (5.92)	Minimal	281 (23.0)
		Mild	415 (33.9)
		Moderate	287 (23.4)
		Severe	241 (19.7)

Abbreviations: ZBI Zarit Burden Interview, PHQ Patient Health Questionnaire, GAD Generalized Anxiety Disorder Assessment

Table 3.

Results of regression analyses between caregiving burden, depression, and anxiety

DV	IV	Unadjusted					Adjusteda
		B	SE	β	t	p	B	SE	β	t	p
ZBI-12	PHQ-9	1.193	0.039	0.658	30.51	< 0.001	0.983	0.041	0.540	23.786	< 0.001
ZBI-12	GAD-7	1.431	0.044	0.682	32.572	< 0.001	1.190	0.045	0.567	26.439	< 0.001
PHQ-9	GAD-7	0.988	0.017	0.854	57.46	< 0.001	0.917	0.020	0.795	46.600	< 0.001

Abbreviations: ZBI Zarit Burden Interview, PHQ Patient Health Questionnaire, GAD Generalized Anxiety Disorder Assessment, IV independent variable, DV dependent variable

^a Data were adjusted for CG gender, CG age, CG education, CG marital status, CG employment, CG household annual income, CR gender, CR age, CR education, CR marital status, CR employment, CR diagnosis, CR illness duration, CR comorbidity of chronic physical illness, CR symptom stability, CR medication compliance, CR insight, relationship with the CR, duration of caregiving for the CR, co-residence with the CR, being the primary CG, presence of other CG, and presence of other CR

Hierarchical regression analyses of caregiving burden, depression, and anxiety

The R-square changes of hierarchical regression analyses are shown in Table 4 and the coefficients of the final models of hierarchical regression analyses are shown in Table 5. All the four categories of characteristics were found to significantly contribute to the explanation of variance in caregiving burden, depression, and anxiety among caregivers, with all the p values of F-tests for R-square changes at each step in the three models less than 0.001. In all the three models, disease-related characteristics contributed the largest proportion of the variance: 16.9%, 12%, and 11.2% for caregiving burden, depression, and anxiety respectively. Overall, the characteristics included in the models explained 36.3%, 27.0%, and 24.0% of the variance in caregiving burden, depression, and anxiety.

Table 4.

R-square changes of hierarchical regression analyses of the effects of caregivers’ sociodemographic, care recipients’ sociodemographic, disease-related, and caregiving-related characteristics on caregiving burden, depression, and anxiety

Characteristicsa	ZBI-12			PHQ-9			GAD-7
	R2 change	F change	p	R2 change	F change	p	R2 change	F change	p
CG sociodemographic characteristics	0.078	5.746	< 0.001	0.082	6.087	< 0.001	0.063	4.599	< 0.001
CR sociodemographic characteristics	0.083	8.690	< 0.001	0.045	4.511	< 0.001	0.043	4.228	< 0.001
Disease-related characteristics	0.169	31.877	< 0.001	0.12	20.112	< 0.001	0.112	18.14	< 0.001
Caregiving-related characteristics	0.033	5.819	< 0.001	0.023	3.554	< 0.001	0.022	3.222	< 0.001

All significance tests were two-tailed

Abbreviations: ZBI Zarit Burden Interview, PHQ Patient Health Questionnaire, GAD Generalized Anxiety Disorder Assessment, CG caregiver, CR care recipient

^a The four categories of characteristics were sequentially included in the regression models in a stepwise manner. R-square change refers to the additional variance explained by the newly added category of characteristics at each step

Table 5.

Final models of hierarchical regression analyses of the effects of caregivers’ sociodemographic, care recipients’ sociodemographic, disease-related, and caregiving-related characteristics on caregiving burden, depression, and anxiety

Characteristics	ZBI-12			PHQ-9			GAD-7
	β	t	p	β	t	p	β	t	p
CG sociodemographic characteristics
CG education (ref. master’s degree or above)
Primary school or below	-0.101	-3.434	< 0.001
Associate degree				0.093	2.014	0.044
CG marital status (ref. never married)
Married or living common-law				-0.133	-2.615	0.009	-0.119	-2.296	0.022
CG employment (ref. full-time)
Part-time				-0.065	-2.328	0.02	-0.072	-2.512	0.012
CR sociodemographic characteristics
CR gender (ref. male)
Female	-0.085	-3.13	0.002	-0.098	-3.374	< 0.001	-0.091	-3.052	0.002
CR age				-0.145	-2.143	0.032
CR marital status (ref. never married)
Divorced or separated	0.058	1.966	0.049	0.086	2.741	0.006
Widowed				0.101	2.869	0.004	0.091	2.539	0.011
CR employment (ref. full-time)
Retired	0.081	2.028	0.043
Disease-related characteristics
CR comorbidity of chronic physical illness	0.078	-3.081	0.002	0.082	-3.038	0.002	0.065	-2.364	0.018
CR symptom stability	-0.232	8.362	< 0.001	-0.182	6.13	< 0.001	-0.165	5.467	< 0.001
CR medication compliance	-0.114	3.775	< 0.001	-0.125	3.851	< 0.001	-0.147	4.449	< 0.001
CR insight	-0.205	-5.961	< 0.001	-0.142	-3.861	< 0.001	-0.133	-3.539	< 0.001
Caregiving-related characteristics
Relationship with the CR (ref. parent)
Child				-0.097	-2.059	0.04
Spouse	-0.113	-2.868	0.004	-0.100	-2.372	0.018	-0.094	-2.194	0.028
Sibling	-0.062	-2.136	0.033	-0.063	-2.032	0.042
Relative other than parent, child, spouse, or sibling	-0.099	-3.142	0.002	-0.099	-2.926	0.004
Others	-0.108	-3.728	< 0.001				-0.071	-2.248	0.025
Co-residence with CR	0.065	-2.158	0.031
Presence of other CR	0.114	-4.479	< 0.001	0.111	-4.075	< 0.001	0.118	-4.25	< 0.001

Only coefficients with statistical significance are shown here (see Supplementary Table 7 for all coefficients), and all significance tests were two-tailed. Bold font indicates the largest five standardized coefficients for each dependent variable

Abbreviations: ZBI Zarit Burden Interview, PHQ Patient Health Questionnaire, GAD Generalized Anxiety Disorder Assessment, CG caregiver, CR care recipient

In the final models of hierarchical regression analyses, care recipients’ symptom stability, medication compliance, and insight were negatively associated with caregiving burden (symptom stability: β = -0.232, t = 8.362, p < 0.001; medication compliance: β = -0.114, t = 3.775, p < 0.001; insight: β = -0.205, t = -5.961, p < 0.001), depression (symptom stability: β = -0.182, t = 6.13, p < 0.001; medication compliance: β = -0.125, t = 3.851, p < 0.001; insight: β = -0.142, t = -3.861, p < 0.001), and anxiety (symptom stability: β = -0.165, t = 5.467, p < 0.001; medication compliance: β = -0.147, t = 4.449, p < 0.001; insight: β = -0.133, t = -3.539, p < 0.001). Compared with caregivers who had never been married, those who were married or living in a common-law relationship exhibited significantly lower levels of depression (β = -0.133, t = -2.615, p = 0.009) and anxiety (β = -0.119, t = -2.296, p = 0.022) but not caregiving burden (β = -0.073, t = -1.532, p = 0.126). Caregivers who were part-time employed exhibited lower levels of depression (β = -0.065, t = -2.328, p = 0.02) and anxiety (β = -0.072, t = -2.512, p = 0.012) but not caregiving burden (β = -0.037, t = -1.417, p = 0.157) compared to those who were full-time employed. Caregivers of females with mental illness showed significantly lower caregiving burden (β = -0.085, t = -3.13, p = 0.002), depression (β = -0.098, t = -3.374, p = < 0.001), and anxiety (β = -0.091, t = -3.052, p = 0.002) than those of males. As the age of care recipients increased, there was a significant reduction in the levels of depression experienced by caregivers (β = -0.145, t = -2.143, p = 0.032). Compared with parent caregivers, caregiving burden was significantly lower among spouse (β = -0.113, t = -2.868, p = 0.004) and sibling caregivers (β = -0.062, t = -2.136, p = 0.033), depression was significantly lower among child (β = -0.097, t = -2.059, p = 0.04), spouse (β = -0.1, t = -2.372, p = 0.018), and sibling caregivers (β = -0.063, t = -2.032, p = 0.042), and anxiety was significantly lower among spouse caregivers (β = -0.094, t = -2.194, p = 0.028). The presence of additional care recipients, aside from the person with mental illness, was found to significantly exacerbate caregiving burden (β = 0.114, t = -4.479, p = < 0.001), depression (β = 0.111, t = -4.075, p = < 0.001), and anxiety (β = 0.118, t = -4.25, p = < 0.001) among caregivers.

Discussion

Main findings

To the best of our knowledge, this is the largest cross-sectional survey that investigated caregiving burden, depression, and anxiety, as well as their associated factors, among informal caregivers of PwMI in China at the national level. Based on a sample of 1,224 participants, the current study found that informal caregivers of PwMI in China experienced a high level of caregiving burden, depression, and anxiety. In this sense, care and support for informal caregivers of PwMI in China proves to be particularly important to improve their own mental health and wellbeing. The current study also found that caregiving burden, depression, and anxiety were inter-correlated with each other among informal caregivers of PwMI, although their respective profiles of associated factors were not entirely the same. The most important factors significantly associated with all three outcomes were disease-related characteristics, particularly care recipients’ symptom stability, medication compliance, and insight. Given the scarcity of research on caregiving burden among informal caregivers of PwMI in China, this study can serve as a benchmark for future studies either tracking the trend of caregiving burden among informal caregivers of PwMI in China or making comparisons across different caregiver populations, while also providing fundamental data for policy-making, advocacy, and service development in the future.

In this study, the participants’ mean score on the ZBI-12 was 25.51 (SD 12.44), and 72.1% of the participants exhibited high burden for a cutoff value of 17 proposed by Bédard et al. [30]. Comparisons of our findings with prior studies are difficult, since there exist wide variations in study design, sampling, inclusion and exclusion criteria of participants, assessment tool, and cutoff value. Also using the Bédard ZBI-12 but with a cutoff value of 19, Wang et al. [44] found that the prevalence of high burden among 253 family caregivers of people with schizophrenia in a Chinese rural county was as high as 95.26%. Zhang et al. [45] recruited 240 family caregivers of adolescents with depression from a tertiary hospital in China and reported a prevalence of 78.8% for caregiving burden measured by the ZBI-22 for a cutoff value of 20. Yu et al. [46] reported a mean score of 42.62 (SD 19.00) on the ZBI-22 among a representative sample of 327 family caregivers of people with schizophrenia in a Chinese rural county but did not report the prevalence of burden. Studies from other countries also observed inconsistent rates of caregiving burden among informal caregivers of PwMI, e.g., 85.3% among family caregivers of outpatients with mental illness (N = 415) from a neuropsychiatric hospital in Nigeria [47], 72.9% for moderate to severe levels of objective burden and 58.6% for severe levels of subjective burden among primary caregivers of patients with mental illness (N = 406) from a psychiatric clinic in Ethiopia [48], and 41.4% among family caregivers of outpatients with mental illness (N = 266) from two mental health clinics in Jordan [49]. A recent meta-analysis [6] calculated the pooled prevalence of caregiving burden among caregivers of PwMI (excluding major cognitive disorders) as 31.67% (95% CI 26.22–37.12), but it also found high heterogeneity in the rate of caregiving burden between studies. Given the socioeconomic and cultural context as a crucial determinant of caregiving burden [50], it is necessary to conduct multinational comparative studies with standardized research methodology to clarify the similarities and differences in caregiving experiences of informal caregivers of PwMI between countries in the future.

This study demonstrated significant inter-correlations between caregiving burden, depression, and anxiety among informal caregivers of PwMI in China. The inter-correlations between caregiving burden, depression, and anxiety have been illustrated in previous studies among informal caregivers of PwMI [9, 51, 52], as well as among those of people with other diseases including stroke [53], cancer [54], and amyotrophic lateral sclerosis [55]. One meta-analysis investigated the association between caregiving burden and depression among informal caregivers of older relatives and found that caregiving burden is a significant risk factor for depression, with very low heterogeneity among individual studies [56]. Another meta-analysis reported a large, positive association between caregiving burden and anxiety in informal caregivers across different caregiving groups [57]. This study further added to the existing empirical evidence base about the close relationships between caregiving burden, depression, and anxiety. From a theoretical perspective, perhaps the mental health ramifications of caregiving burden are best understood by Pearlin’s stress-process model [10]. Considering the detrimental effects of caregivers’ mental ill-health both on their quality of life [7] and on the quality of care they can provide for care recipients [58], it is of great importance to buffer the strain caused by caregiving activities for PwMI.

This study found that care recipients’ disease-related characteristics, particularly symptom stability, medication compliance, and insight, were most significantly associated with caregiving burden, depression, and anxiety. Previous studies also validated a consistently significant effect of symptom severity on caregiver wellbeing among informal caregivers of PwMI [3, 12, 59]. Psychopathological symptoms of mental illness, such as delusions, hallucinations, mania, and depression, may severely impact the person’s interpersonal relationships, family dynamics, and social functioning. Informal caregivers often have to manage the emotional and behavioral disturbances incurred by these symptoms, which can lead to significant stress, especially when they lack effective coping skills. The prominent, or even dominant in some cases, influence of psychopathological symptoms on caregiving burden can also be observed in other caregiver populations, including dementia [60–62], Parkinson’s disease [63], multiple sclerosis [64], and stroke [65]. In addition, caregiving burden is presumably dependent on how well care recipients can care for themselves, such as adhering to their medications and having insight into their conditions. The current study demonstrated that care recipients’ medication compliance and insight are important predictors of caregiving burden, depression, and anxiety, which justifies empowering the persons with mental illness in their recovery by improving self-management and uptake of mental health care to be beneficial not only for the persons but also for their caregivers.

Regarding the care recipient’s diagnosis, univariate analyses in this study showed that informal caregivers of people with autism seemed to have the highest levels of caregiving burden, depression, and anxiety, followed by those of people with schizophrenia, bipolar disorder, and depressive disorder (see Supplementary Table 4). This may be due to more severe functional impairment, earlier onset of illness, and longer duration of caregiving among people with autism. However, after adjusting for other characteristics in this study, the effects of the care recipient’s diagnosis on caregiving burden, depression, and anxiety were absent (see Supplementary Table 7 for more details of hierarchical regression analyses). To date, there have been few studies comparing caregiving burden, depression, and anxiety between informal caregivers of people with different diagnoses of mental illness. In their meta-analysis, Cham et al. [6] found that the prevalence of caregiving burden was higher among informal caregivers of people with psychosis (35.88%; 95% CI: 27.03, 44.72) than those of people with non-psychotic mental illness (26.82%; 95% CI 17.98, 35.67). However, the studies included in this meta-analysis exhibited high heterogeneity, and it is not without question to categorize all mental illnesses other than psychosis into one sub-group which might result in more subtle differences across illness types being overlooked. Another systematic review synthesized the comparative literature examining caregiving burden and psychological functioning between caregivers of people with schizophrenia spectrum disorders and bipolar disorder and found a lack of differentiation between these two groups [13]. Considering the broader literature on caregiving experiences in other health conditions which also failed to capture the effect of diagnosis on caregiving burden and psychological functioning among caregivers, the authors concluded that diagnosis alone may not influence the caregiving experiences as much as other transdiagnostic illness characteristics or characteristics of the caregiver themselves [13].

Our investigation indicated a strong association between care recipient gender and caregiving burden, depression, and anxiety. Specifically, it was found that male care recipients were significantly associated with higher levels of caregiving burden, depression, and anxiety. Evidence regarding the effect of care recipient gender on caregiving burden is mixed, with some demonstrating higher burden in male patients [66], some demonstrating higher burden in female ones [67], and others demonstrating comparable burden in the two groups [68, 69]. One major reason for higher burden in male patients may be that males with mental illness are more likely to exhibit aggressive and violent behaviors than females [70], thus causing more distress and burden among their caregivers. Besides, in China’s traditional culture, males are deemed as the main pillars of financial support for the family, as expressed in the saying, ‘men lead outside and women lead inside.’ However, mental illness can severely impact the patients’ ability to work and reduce their job opportunities, leaving them unemployed for long periods [71]. In such cases, a larger share of the burden for earning money to support the family will be naturally laid on the caregivers. The gap between the expectation placed on males’ financial responsibilities and the reality may also contribute to the caregivers’ feelings of frustration.

This study also demonstrated that parent caregivers had the highest levels of caregiving burden, depression, and anxiety among different caregiving relationship groups (see Supplementary Table 5 for more details). Likewise, Yu et al. [72] found that, in a sample of 264 family caregivers of people with schizophrenia in rural China, parent caregivers reported significantly higher subjective burden, depression, and anxiety than spouse caregivers, although both types of caregivers reported engaging in similar activities and reported comparable levels of objective burden. In China, parents constitute the largest proportion of informal caregivers of PwMI, as has been shown in this study and others [73, 74]. Compared with parents, it is not uncommon that spouses and other relatives would not invest as much effort in caregiving for the person with mental illness in families and may even eventually relinquish their caregiving responsibilities by leaving or institutionalizing the person. In contrast, parents typically would continue to care for their child with mental illness even when he or she is already an adult, leading to the so-called “reverse intergenerational care” model [75]. However, considering the onset of the majority of mental illnesses in early adulthood [76], parent caregivers, especially those of people with chronic mental illness, are often in middle or old age and may face an increasing number of caregiving needs themselves. Such a family structure, where the elderly parents care for their adult child with mental illness, can expose the parents to a much higher level of burden.

One strength of this study is that, by including caregiving burden, depression, and anxiety as dependent variables in a single study, it could elucidate the differences in their respective profiles of associated factors which have rarely been explored comprehensively in previous literature on informal caregiving. One such difference found in this study is that, while formal or common-law marriage was a protective factor for caregiver depression and anxiety, it was not for caregiving burden among informal caregivers of PwMI in China (see Supplementary Table 2 for the ZBI-12, PHQ-9, and GAD-7 scores of different caregiver marital status groups). In our sample, the typical caregiver profile was consistent with a middle-aged mother providing care for her unmarried dependent children. In China, as in many other countries, females often bear the primary responsibility for family caregiving of PwMI [77]. If the female caregiver is married or living common-law, her male partner may be able to provide some emotional or instrumental support for her, but may not share the specific caregiving responsibilities, leaving the female caregiver providing care for their child alone and leading to a phenomena of “widow-style parenting” in contemporary China [78]. Sometimes, the female caregiver may even need to care for her husband, as well as her parents-in-law, while taking care of her mentally ill child, which further exacerbates her burden.

In China, the needs of informal caregivers of PwMI have long remained at the periphery of the government’s social care and support system. With a critical shortfall in formal care resources to address the needs of PwMI, China’s mental health system has come to rely heavily on the informal type of care provided by the families and wider social networks of PwMI. Yet, many of these informal caregivers are ill-equipped with the requisite knowledge and skills to care for PwMI. Some are even elderly themselves, in need of care from others rather than capable of providing it. To this day, very few services have been established in China to support these caregivers. While mental health policies and legislation in China have clearly delineated the obligations of informal caregivers in providing care and guardianship for PwMI, they have paid little attention to the rights these caregivers shall enjoy to receive essential support for their own health and wellbeing. Although there exists a financial subsidy policy to incentivize informal caregivers to fulfill their guardianship responsibilities, it is used more for rewards rather than universal benefits, and its effectiveness in alleviating caregiving burden among informal caregivers of PwMI has yet to be empirically substantiated. Without sufficient support, the weight of caregiving responsibilities can become an insurmountable burden for informal caregivers, leaving them susceptible to mental and physical ill-health. As revealed in the current study, informal caregivers of PwMI in China were experiencing a high level of caregiving burden, depression, and anxiety. It is imperative that more attention be devoted to safeguarding the health and wellbeing of these caregivers. After all, it is inconceivable that someone struggling with their own health conditions could be expected to provide quality care for another.

Limitations

The interpretation of our findings should be considered with the following limitations. First, this study employed a cross-sectional design which did not allow assessment of the direction of effect for the associations described above. In future, longitudinal studies are needed to verify the causality between the variables investigated. Second, this study used a non-probability sampling method to recruit the participants, resulting in the representativeness being liable to doubt. Informal caregivers of people with schizophrenia, bipolar disorder, depressive disorder, and autism were over-represented in this study. Although the multivariate analysis found no significant effect of diagnosis on caregiver burden, depression, and anxiety among these four groups of caregivers, it is plausible that varying levels of caregiver burden, depression, and anxiety might be experienced among caregivers of people with other mental disorders. On the other hand, this study did not take into consideration the effect of mental illness symptomatology on caregiver burden, depression, and anxiety. It is possible that various types of psychiatric symptoms are related with different levels of caregiver burden. Therefore, the overall level of caregiver burden in the study sample might be contingent to the distribution of mental illness diagnosis and symptomatology. Future research is needed to compare the burden faced by caregivers across a broader range of mental disorders in China. Additionally, a transdiagnostic approach can be incorporated into caregiving studies, such as using transdiagnostic symptom assessment tools to measure the effects of different psychiatric symptoms on caregiver burden. Besides, the more economically developed eastern region of China contributed a much larger percent of participants than other regions, which makes it necessary to exercise caution when generalizing our findings to the entire country. It is also conceivable that those with higher levels of caregiving burden, depression, and anxiety were more likely to be attracted to participate in this study, leading to the scores of caregiving burden, depression, and anxiety being overestimated. In addition, the questionnaires in this study were distributed via online platforms, which may exclude potential participants who lack access to the Internet or familiarity with online survey tools, particularly older informal caregivers and those living in rural areas. However, considering that the population of informal caregivers of PwMI is largely hidden in Chinese society, it may be difficult to recruit a representative sample of informal caregivers of PwMI in China. Third, the data collected in this study were self-reported by caregivers. Thus, there is a potential for subjective and memory biases, particularly regarding disease-related characteristics such as care recipients’ symptom stability, medication compliance, and insight, which may influence the strength of associations identified in this study. For instance, caregivers experiencing higher levels of depression and anxiety may be more prone to catastrophizing the caregiving situations they are faced with [79] and therefore overestimating the severity of their care recipients’ illness. Last, this study focused solely on the effects of four categories of basic information regarding caregiver-care recipient dyads on caregiving burden, depression, and anxiety among caregivers. Undoubtedly, there exist other factors that may be associated with caregiving burden, depression, and anxiety among caregivers, such as caregivers’ coping strategies, social support, and access to formal mental health care resources. These factors, along with their interactions, should be explored further in future studies. Despite these limitations, the current study still represents the latest effort to delineate the overall situation of caregiving burden, depression, and anxiety among Chinese informal caregivers of PwMI at the national level, and can inform future policies and actions to relieve the burden experienced by informal caregivers of PwMI in China.

Implications for practice

Based on the findings of this study, several significant implications can be made to push forward the development of a comprehensive social care and support system for informal caregivers of PwMI in China. First, advocacy efforts must be strengthened to raise public awareness of the needs of informal caregivers of PwMI. Second, the contributions of these caregivers to China’s mental health system should be formally recognized in mental health policies and legislation, with explicit provisions outlining the essential forms of support that should be in place to alleviate their burden. Third, a range of supportive strategies and services for informal caregivers of PwMI should be established and evaluated in the Chinese context, including psychological counselling, skills training, respite care, caregiver support groups, care leave, and cash benefits. Natural support networks of caregivers could also be mobilized to enhance their resilience. Fourth, mental health clinicians should be trained and motivated to identify and address the needs of informal caregivers of their clients. Clinicians should be aware that informal caregivers of PwMI may themselves be at high risk for mental illness. Incorporating screening tools for caregiving burden into routine clinical practice, and referring caregivers with high burden to appropriate support services, could be vital in preventing the mental health consequences of caregiving burden.

Conclusion

As the largest cross-sectional survey on caregiving experiences of informal caregivers of PwMI in China, the current study reported a high level of caregiving burden, depression, and anxiety among informal caregivers of PwMI in China. This study further investigated the caregivers’ sociodemographic, care recipients’ sociodemographic and disease-related, and caregiving-related characteristics associated with caregiving burden, depression, and anxiety and found that their respective profiles of associated factors were not entirely the same. The most important factors associated with all three outcomes were disease-related characteristics, particularly care recipients’ symptom stability, medication compliance, and insight. Compared with informal caregivers of females with mental illness, those of males with mental illness exhibited significantly higher levels of caregiving burden, depression, and anxiety. Care recipients’ diagnosis was not associated with caregiving burden, depression, and anxiety in multivariate analyses. Intriguingly, our results showed that, while formal or common-law marriage was a protective factor for caregiver depression and anxiety, it was not for caregiving burden. Our findings can provide an important benchmark for comparative and longitudinal studies among informal caregivers of PwMI in China and act as an impetus for future actions to relieve caregiving burden, depression, and anxiety among informal caregivers of PwMI in China.

Abbreviations

PwMI

People with mental illness

ZBI

Zarit Burden Interview

PHQ

Patient Health Questionnaire

GAD

Generalized Anxiety Disorder Scale

CG

Caregiver

CR

Care recipient

RMB

Renminbi

Authors’ contributions

H.Y. and K.L. designed the study. C.L. revised the questionnaire and assisted with the collection of data. H.Y. analyzed the data and drafted the manuscript. S.H. and Z.H. participated in the explanations of the results. J.C. and Y.X. supervised the study. All authors provided a critical review of the manuscript and approved the final draft for publication.

Funding

The study was funded by grants from the National Social Science Fund of China (H.Y.; No. 22CSH085); the China Medical Board (H.Y.; No. 22–480); the Shanghai Sailing Program (H.Y.; No. 21YF1439600); the Jinge Fellowship of Beijing Yifang Foundation (H.Y.); and Shanghai “Rising Stars of Medical Talent” Youth Development Program for Youth Medical Talents - Specialist Program (H.Y.; No. 2024-70). The funders had no role in study design, data collection, data analysis, data interpretation, or manuscript writing.

Data availability

The de-identified data are available on reasonable request to the corresponding authors.

Declarations

Ethics approval and consent to participate

This study was performed in accordance with the Declaration of Helsinki and approved by the Ethics Committee of Shanghai Mental Health Center, Shanghai Jiao Tong University (Reference Number: 2023–74). The informed consent form was presented on the first page of the online questionnaire distributed in this study and only those who checked the consent box on the form were guided to complete the remaining part of the questionnaire.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.