Caregiving experience associated with unpaid carers of persons with schizophrenia: a scoping review

ABSTRACT This scoping review focuses on how the caregiving experience of unpaid carers of persons with schizophrenia (CPSs) is understood in the literature. One hundred and eighteen studies were included. Publications have steadily increased over the past two decades. Most studies were derived from India, the UK, and China and were quantitative research. Financial problems, disruption to social life, and family relationships were commonly evaluated to be objective burdens, while care recipients relapsing, CPSs suffering from violence from care recipients, and experiencing discrimination were identified as subjective burdens. The effectiveness of care services and the positive feelings and physical impacts of CPSs need to be further discussed.


Background
Schizophrenia is a mental health problem characterized by persistent difficulties with cognitive or thinking skills, such as hallucinations and delusions (WHO, 2022).Ribé et al. (2018) note that schizophrenia has far-reaching consequences not only for the life of individuals experiencing it but also for those caring for them.Although there is no agreed definition of unpaid carers (hereafter carers) in the literature (Tucker, Barker, & Gregoire, 1998), a carer is anyone who looks after a family member, partner, or friend who experiences chronic illness, frailty, disability, or a mental health problem (NHS, 2022).Carers may experience physical and emotional stress (Nuraini, Tumanggor, Hungerford, Lees, & Cleary, 2021), difficulties in maintaining family relationships (Jungbauer, Wittmund, Dietrich, & Angermeyer, 2004), and issues in participating in the labor market, all of which have been shown to lower their quality of life (Kayaalp, Page, & Rospenda, 2021;Ribé et al., 2018;Sales, 2003).
The concept of carer burden has been used to understand the extent to which carers perceive the impacts on their emotional and physical health, social life, and finances as a result of being a carer (Koschorke et al., 2014).
Evidence has indicated that carer burden is associated with personal, social, and economic challenges to the carer (Askey, Holmshaw, Gamble, & Gray, 2009;Schulz & Sherwood, 2008), especially carers of people with a mental illness who struggle to cope with cognitive and behavioral manifestations of the illness at home (McCann, Bamberg, & McCann, 2015).Scholars generally distinguish carer burden into two separate categories: objective and subjective burdens (Malhotra, 2016).Objective burdens refer to changes to daily life resulting from caring for a relative with a chronic illness, for example disruption to routine activities, loss of employment opportunities, and disconnecting from social networks (Jagannathan, Thirthalli, Hamza, Nagendra, & Gangadhar, 2014;Srivastava, 2005).Subjective burdens are related to negative emotions or feelings experienced by carers, such as depression, anxiety, or anger (Lippi, 2016).
The burdens of care experienced by CPSs have been studied in various regions and cultures, demonstrating the extent to which this is a global issue.Ferriter and Huband (2003) reported that UK carers experienced several aspects of burden, which included emotional burden, financial burden, and negative self-esteem.Studies have also investigated the influence on carer's mental health.For example, in Australia, Hayes, Hawthorne, Farhall, O'Hanlon, and Harvey (2015) illustrated that over 40% of carers of people with mental illness were likely to develop mental health problems, such as anxiety and depression.These psychological stresses are sometimes hidden (Mizuno, Takataya, Kamizawa, Sakai, & Yamazaki, 2013).Besides, some studies focused on understanding the affecting factors of carer burden.A study in India identified that the duration of illness of persons with schizophrenia and carers' perceived social support were significant predictors of both objective and subjective burdens (Jagannathan, Thirthalli, Hamza, Nagendra, & Gangadhar, 2014).A cross-sectional study conducted in the USA analyzed the association of carer burden with positive symptoms (exaggerations in functions, such as violence or self-harm) and negative symptoms (a deficit in function, such as slowness or overdependence) of schizophrenia and found that subjective burdens were related to the severity of symptoms, while objective burdens were related to the severity of positive symptom behaviors (Provencher & Mueser, 1997).Furthermore, a Taiwanese study found that the level of carers' burdens was influenced by caregiving tasks, a lack of professional support and family conflicts (Huang, Hung, Sun, Lin, & Chen, 2009).The above studies show that burdens were explored via various approaches and perspectives.
Although academic knowledge is increasing as to how carer burden is experienced by CPSs, the practice implications of such knowledge and how it can be used to reduce carer burden are not well understood.Therefore, a review and reflection of the current evidence base is timely.The key rationale of this scoping review is to highlight where attention on carer burden has been addressed and where knowledge gaps remain.This is imperative to inform future research and advance policies and practices in the field of CPSs.Arksey and O'Malley (2005) identify that a scoping review may be used to address a body of literature and is suitable for reviewing many different research designs on a given topic.Scoping reviews allow academics to rapidly review key concepts within a body of literature and to map the range of evidence available (Arksey & O'Malley, 2005;Klein, 2021;Munn et al., 2018).They also allow researchers to identify gaps in the existing literature where no research has been conducted and which may inform future research on a particular topic area (Anderson, Allen, Peckham, & Goodwin, 2008).For this review, the five-stage 1 method for scoping reviews developed by Arksey and O'Malley was adopted and PRISMA guidelines used to help standardize reporting.

Stage one: identifying research questions
This scoping review was guided by the overall question of how the objective and subjective burdens of caring for a person with schizophrenia and their caregiving experiences are understood in the current literature.No limitations on the population, region, age, gender, and geographical background were used.By answering the research question above, the review attempted to: (1) Understand the definition and sociodemographic characteristics of CPSs found in the previous literature; (2) Identify objective and subjective burdens experienced by CPSs; (3) Highlight the formal support (e.g., health and social services) or informal supports that CPSs use in their caregiving role and its impact

Stage two: identifying relevant studies -eligibility criteria and electronic search strategy
Database searches were conducted throughout November 2021.Given that Arksey and O'Malley (2005) place emphasis on searching various sources, four electronic databases were searched and yielded a total of 3,050 studies.The search terms used for searching the four databases are provided in Table 1.This consisted of 1,325 studies in Scopus, 597 in IBSS, 723 in Web of Science, and 405 in APA PsycNet.Restrictions on peer-reviewed literature published in English and Chinese (due to limited translation services) were set.No limits were set on publication period, study design, or methodology.Restrictions on peer-reviewed literature published in English and Chinese (due to limited translation services) were set.No limits were set on publication period, study design, or methodology.

Stage three: studies selection
At this stage, the literature was checked for duplicates.Of the 3,050 studies selected, 727 were duplicates, which left 2,323 pieces of literature for title and abstract screening.The process of study selection was based on the inclusion and exclusion criteria outlined in Table 2. Studies which did not explicitly focus on carers' experience of caring for persons with schizophrenia were excluded.For example, abstracts which indicated that participants were carers of people with mental health problems more broadly were excluded.Also, the literature was excluded if they focused on testing the adaptation and validation of a carer burden scale within a country because the research findings were merely to identify the internal consistency, internal structure, and validity/reliability of the scale rather than reporting carers' burden.Studies were included if they investigated a topic that was relevant to carer burden of CRSs or compared the difference in carer burden between CPSs and carers of people with other mental illnesses.A total of 115 pieces of literature remained after screening research titles and abstracts based on the above criteria, of which 24 studies were excluded after full-text screening (reasons for exclusion are listed in Figure 1).Relevant literature was also identified through ongoing hand searches of reference lists and bibliographies of included articles.This process yielded an additional 27 studies.As shown in Figure 1, a total of 118 pieces of peer-reviewed journal articles, including hand searches, were selected to be included and reviewed after the full-text screening.

Stage four: charting the data
This stage generated research data relevant to carer burden of CPSs.
Literature accepted in the screening stage was charted on a Microsoft Excel spreadsheet to show how each article answered the research questions.The variables presented in the data-charting form included

Stage five: collating, summarizing, and reporting
In this stage, the analyzed data were reported numerically and thematically based on the Microsoft Excel spreadsheet, which were generated to answer the overarching review question in stage four.

Result
The analyzed data are first reported with the general characteristics of the reviewed literature, which consisted of the country where the research was conducted, and the year of publication, research methods, and designs are presented.Second, four themes were generated through thematic analysis.

General characteristics of the literature
No limits were placed on the publication date within this scoping review.As shown in Figure 2, there has been an increase -albeit unequal -in the publication trend for carer burden literature over the past two decades.Within the reviewed studies, three articles were found prior to 1996 (Hoenig & Hamilton, 1966;Salleh, 1994;Winefield & Harvey, 1994).The number of publications slightly increased between 1997 and 2001, and the publication trend has more than doubled every 5 years from 2002 to 2016.The number of publications in the past five-year period (2017-2021) is 33.The included studies originated from a total of 32 countries.The majority of studies were carried out in Asia (n = 61), of which the most were conducted in India (n = 21), followed by China (n = 10) and Hong Kong (n = 7).The next most common region was Europe (n = 38), of which the UK (n = 14) was the most represented country.Twelve studies came from North America.Ten were conducted in the USA.There was limited literature from South America and Africa, consisting of four studies covering Chile, four studies based in Nigeria, and one study from Swaziland and South Africa.
In terms of the research design, 88 studies employed quantitative methods.Of these studies, the most frequent research designs were cross-sessional studies (n = 79).Surprisingly, only nine studies employed a longitudinal design.Among the longitudinal studies, they were published between 1998 and 2021, and the follow-up periods were between 15 years and 3 months.Six of them were employed interventions, such as a stress management training program, psychoeducation and mutual support programs, or medical treatment programs, used to examine whether carer burden and distress changed after the intervention was given.Three studies found that there were no significant differences in the tested outcomes (carer burden, positive experiences, and carer distress).Diverse measures were employed to examine the level of carer burden experienced by CPSs in the quantitative studies, while two qualitative studies also used validated scales to elicit carers' caregiving experience (Hernandez & Barrio, 2015;Poon, Joubert, & Harvey, 2013).Across all studies, 18 unique instruments (or 3"scales") were used to examine carer burden.Appendix 1 shows the various instruments used in the reviewed studies.The Zarit Burden Interview (ZBI) was employed most often (n = 19), followed by Family Burden Interview Schedule (FBIS) (n = 19), Involvement Evaluation Questionnaire (IEQ) (n = 11), and Burden Assessment Schedule (BAS) (n = 11).
Thirty of the included studies used qualitative methods to collect data (5 of these studies were mixed methods).Most theses employed in-depth interviews (n = 21).The author examined the qualitative rigor of the reviewed literature based on the components of trustworthiness purposed by Thomas and Magilvy (2011) 2 and found that among the qualitative research, all covered dependability (providing a detailed description of the research methods), 30 studies explained their procedures for enhancing credibility, and seven research studies discussed transferability.One study mentioned confirmability (a self-critical attitude by researchers into how their preconceptions affect the research process).The five remaining studies employed mixed-methods consisting of a cross-sessional study and qualitative interviews.
There have been various topic areas covered in the reviewed studies.These can be allocated into two main categories of research.The first category focuses on the individual circumstances of CPSs, while the second category focuses on the dynamic relationship between CPSs and the social environment.A total of 116 studies covered individual-level circumstances in the reviewed studies, including the topics related to carer burden (n = 84), psychological conditions (n = 46), caregiving experience (n = 27), coping strategies (n = 15), quality of life (n = 13), knowledge about schizophrenia (n = 8), the needs for CPSs (n = 4), perceived carer' role (n = 2), and abuse behavior (n = 1).Issues pertaining to the carers' social environment were found in 31 articles, including the levels of social support received by CPSs in 21 studies, the experience of social discrimination in seven, and family functioning in four studies.Apart from the topic of carer burden, 39% of reviewed studies covered carers' psychological conditions and 17% covered caregiving experience, indicating that assessing the psychological health of CPSs and exploring the caregiving experience can be seen to dominate the literature.

Theme one: definitions and socio-demographic characteristics of carers
Definitions of the term "carer" lacks any standard definition on which to base inclusion criteria for empirical research within academic and practical fields (Molyneaux, Butchard, Simpson, & Murray, 2011;O'Connor, 2007).This is reflected in the reviewed studies.Only 18 out of 118 studies provided a definition of carers and those that did provide diverse definitions.Most identified carers as family members or friends intimately involved in their everyday care.Some authors (Grover et al., 2012;Kate, Grover, Kulhara, & Nehra, 2013b;Liu et al., 2015) further indicated that carers were the persons who had been caring for care recipients for at least a year.Tucker, Barker, and Gregoire (1998) defined family carers as ones without whom the care recipient would be unable to live in the community.In one study, carers were identified by the care recipient who decided which family member or friend was most directly involved in their care (Breitborde, López, & Nuechterlein, 2009;Perlick et al., 2006).The remaining definitions identified carers in relation to the extent of caring work undertaken as a non-paid and nonprofessional person.Few studies identified carers according to the caregiving tasks that carers might assist the care recipients during the caregiving, such as supervising medications, bringing the patient to the hospital, or liaising with the treating team (Arun, Inbakamal, Tharyan, & Premkumar, 2018;Grover et al., 2012;Kate, Grover, Kulhara, & Nehra, 2013a;Nehra, Chakrabarti, Kulhara, & Sharma, 2005).
Although most reviewed studies did not provide a definition of carers, it could be identified (or implied, in many instances) through the recruitment criteria of research participants.A total of 68 studies provided the recruitment criteria on carers (research participants), which varied across the studies.They could be categorized into the following items, including the age of carers in 42 studies, living with people with schizophrenia in 24 studies, the duration of involvement in care in 17 studies, non-psychiatric disorder in 15 studies, the time (hours/days) spent on caregiving in 12 studies, definitions on caregiving tasks in eight studies, and relations with care recipient in five studies.In 18 out of 118 studies, they initially identified care recipients, who were diagnosed with schizophrenia, and then recruited their carers to participate in research, meaning that carers were identified by care recipients.In summary, most research required that carers were at least aged 18 years and above, have been taking care of a person with schizophrenia for at least 1 year, and were first-degree or a close relative who could participate in the study, such as a parent, spouse, sibling, or child.The characteristics of CPSs who participated in the studies were further summarized (see Appendix 1).The majority of carers were middle aged (between 45 and 59 years).More female carers males were present in the most reviewed studies, but there were eight studies in which more male carers participated than female carers.They were mostly married, employed, and parents of persons with schizophrenia.

Theme two: components of objective burden
This theme presented components of objective burden where the research findings of reviewed studies were related to the disruption to carers' finances, social activities/networks, family relationship, and physical health.

Financial burden
Numerous studies identified financial burden as a major aspect of objective burden (Semran, Woon, & Marhani, 2019), which may be because of longterm medical needs or a reduced ability of care recipients to work (Al-Sawafi, Lovell, Renwick, & Husain, 2021;Attepe Özden & Tuncay, 2018;Chen et al., 2019;Gater et al., 2014;Nuraini, Tumanggor, Hungerford, Lees, & Cleary, 2021).Moreover, CPSs often had to give up work entirely or change the way that they worked, such as working part-time to fulfill caregiving tasks (Gater et al., 2014;Liu et al., 2015;Poon, Joubert, & Harvey, 2013).A Chinese study that compared gender differences in carer burden found that female carers reported significantly higher financial burdens than male carers as female carers were mainly unemployed and relied on other family members to provide financial support (Yu et al., 2019).Semran, Woon, and Marhani (2019) noted cases in which carers had lower financial burdens if their relative with schizophrenia had a higher income or full-time job.

Disruption to social activities
Restrictions on social activities due to caregiving tasks can be seen as a key impact on carers (Verma, Grover, & Chakrabarti, 2021).The literature notes that carers had less time for themselves and needed to be on call for emergencies where people with schizophrenia were highly dependent on them (Brain, Kymes, DiBenedetti, Brevig, & Velligan, 2018, Chen et al., 2019;Mhaule & Ntswane-Lebang, 2009).Also, carers often reduced attendance at activities outside the home or might take a relative being cared for to social events due to worries about them staying at home alone (Poon, Joubert, & Harvey, 2013).This caused a gradual loss of social contact for carers (Jungbauer, Wittmund, Dietrich, & Angermeyer, 2004).One study showed that CPSs were more likely to change personal plans than carers of people with an affective disorder (Ignatova, Kamusheva, Petrova, & Onchev, 2019).

Damage to relationships within the family
This sub-theme consisted of the relationship between carers and care recipients, and the relationship between carers and other family members excluding care recipients.First, studies mentioned that carers were sensitive about their communication with the care recipient and experienced difficultly in interacting in appropriate ways because the ill relatives were moody, solitary, and/ or aggressive (Jungbauer, Wittmund, Dietrich, & Angermeyer, 2004;Poon, Joubert, & Harvey, 2013), especially during care recipients' relapses.Second, the conditions of schizophrenia also challenged the relationships between the carer and other family members (Hernandez & Barrio, 2015).For example, Liu et al. (2015) reported that arguments about caregiving tasks, such as caring expenditure and attitudes toward treatment, have frequently existed between spouses, which might damage their relationship.

Effect on physical health
On rare occasions, studies reported on the negative impacts on carers' physical health due to their care responsibilities.Hernandez and Barrio (2015) found that physical health problems could be attributed to stressors linked to caregiving responsibilities.Carers' sleep might also be disturbed because of the behavior of people with schizophrenia (Gater et al., 2014).Yet, the impact on physical health, as a part of measuring objective burden, was rarely reported as a significant burden.For example, Verma, Grover, and Chakrabarti (2021) compared the areas of objective burden and found that effects on the physical health had the lowest score of burden compared to other areas.

Theme three: factors affecting subjective burden
The research findings related to the subjective burden experienced by carers were classified into this theme.This theme presents the specific circumstances under which the subjective burden would increase for .The sub-themes include the change in the course of psychosis in people with schizophrenia, carers suffering from aggression/violence from the care recipient, and experiences of discrimination from wider society.

The course of psychosis in relatives with schizophrenia
The course of psychosis was divided into three stages.First, carers indicated that the first onset of schizophrenia in the relative was an extremely burdensome experience because the psychotic symptoms were unknown, leading to feelings of powerlessness, fear, despair, and frustration (Gater et al., 2014;Hernandez & Barrio, 2015;Jungbauer, Wittmund, Dietrich, & Angermeyer, 2004).Second, carers often became confused, frustrated, and/ or fearful when the relative with schizophrenia was discharged from hospital (Milliken, 2001;Mizuno, Takataya, Kamizawa, Sakai, & Yamazaki, 2013).Studies have shown that the number of hospitalizations in the past 3 years could be a predictor of subjective burden (Gutiérrez-Maldonado, Caqueo-Urízar, & Kavanagh, 2005) and expressed emotion (Gupta & Mohanty, 2016).Third, carers experienced anxiety when thinking about the future of relatives with schizophrenia (Nuraini, Tumanggor, Hungerford, Lees, & Cleary, 2021).Ignatova, Kamusheva, Petrova, and Onchev (2019) found that CPSs were more worried about the future of the relative than carers of individuals with affective disorder.Furthermore, an association between the duration of schizophrenia and carer burden was found in a study conducted by (Rudge & Morse, 2004).Jungbauer, Wittmund, Dietrich, and Angermeyer (2004) found that a common risk in daily life was the increased potential of conflict between carers and care recipients in cases where an ill relative became aggressive during relapse.Studies highlighted that the subjective burden of carers was partly influenced by violent behaviors by the relative with schizophrenia and that providing care for a relative with schizophrenia increased stress due to increased risks of violence (Al-Sawafi, Lovell, Renwick, & Husain, 2021;Bademli & Lok, 2020;Ferriter & Huband, 2003;Mhaule & Ntswane-Lebang, 2009).By contrast, Verma, Grover, and Chakrabarti (2021) found that there was a significant reduction in carers' abusive behavior toward people with schizophrenia 3 months after the care recipient began clozapine treatment.This indicates that abusive behaviors within families can be bidirectional.

Discrimination
Negative comments and actions from society, neighbors, and kin toward ill relatives and family members were also associated with increases in carer burden (Hernandez & Barrio, 2015;Mhaule & Ntswane-Lebang, 2009).Most of the carers experienced social exclusion and stigmatization because of caring for relatives of schizophrenia (Attepe Özden & Tuncay, 2018).A study conducted in India mentioned that feelings of grief and depression were associated with the highest score with stigma assessment (Thara & Srinivasan, 2000).Also, social discrimination created a sense of isolation for families with mental illness (Attepe Özden & Tuncay, 2018) and compelled carers to keep the ill relative a secret or to reduce engagement in society to avoid negative reactions from the wider community (Wong, Kong, Tu, & Frasso, 2018).

Theme four: caregiving experience
This theme summarizes different caregiving experiences of CPSs which have been explored in the reviewed studies.The sub-themes presented are as follows: lack of knowledge about the schizophrenia, the process of seeking help; carers' services/supports network, and traditional social norms and positive experience of caregiving.A total of 21 studies aimed to explore the caregiving experience in the reviewed studies.

Lack of knowledge about schizophrenia
Carers often had no knowledge of schizophrenia when they began caring (Al-Sawafi, Lovell, Renwick, & Husain, 2021;Attepe Özden & Tuncay, 2018).Several consequences of this lack of knowledge were noted.It could lead to delayed diagnoses (Mizuno, Takataya, Kamizawa, Sakai, & Yamazaki, 2013), seeking treatment outside of mental health services (Jung, 2000;Mizuno, Takataya, Kamizawa, Sakai, & Yamazaki, 2013;Nuraini, Tumanggor, Hungerford, Lees, & Cleary, 2021) and difficulties in dealing with the symptoms of schizophrenia (Jungbauer, Wittmund, Dietrich, & Angermeyer, 2004).Additionally, a lack of knowledge about schizophrenia impacts on the types of coping strategies that CPSs used.For example, Rahmani et al. (2019) and Hanzawa et al. (2010) found that seeking information about the illness and treatment was the least used coping strategy.Studies also found that little understanding among CPSs on the future course of the illness led to feelings of guilt, powerlessness, and despair (Imkome & Waraassawapati, 2018).

The process of seeking help
Research indicates that CPSs most commonly sought problem-focused and social support as coping strategies rather than avoiding seeking help (Chadda, Singh, & Ganguly, 2007;Verma, Grover, & Chakrabarti, 2021).Research by Kate, Grover, Kulhara, & Nehra (2013b) identifies that a frequent strategy adopted by CPSs was to try and understand the illness, through consulting with doctors about the problem.In other words, coping strategies used by CPSs were mainly focused on gaining information about the illness.However, Knock, Kline, Schiffman, Maynard, and Reeves (2011) note that mental health-care providers were regarded as unhelpful and neglectful by CPSs.For example, CPSs indicated inadequate community psychiatric services (Mhaule & Ntswane-Lebang, 2009).Tuck, du Mont, Evans, and Shupe (1997) and Rudge and Morse (2004) reports that consultations with professionals often yielded confusing advice for CPSs.By contrast, informal services, family and self-help groups, were perceived as helpful (Ferriter & Huband, 2003).A study focusing on mother carers' coping strategies found that mothers' anxiety and bitterness related to the schizophrenia of their children led them to stop solving problems related to the illness over time (Kasperek-Zimowska, Józefa Steuden, & Charzyńska, 2013).Poon, Joubert, and Harvey (2013) report that the focus of mental health services is often on the provision of services to people with mental health problems, with less emphasis placed on support services for CPSs.The reviewed research rarely explored the effect of social services and/or support on carers.Appendix 1 shows the social services and informal supports used by CPSs, such as community mental health centers and respite care.Overall, six studies focused on the effectiveness of psychoeducation courses and mutual support groups for CPSs.In addition, 17 studies recorded the services or supports CPSs used, which included the social services department in seven studies, faith/spirituality in four studies, friends in four studies, family in two studies, and neighbors in one study.Only one research study conducted in Japan aimed to investigate attitudes of CPSs toward mental health welfare policies, and the services provided by family associations (Mizuno, Takataya, Kamizawa, Sakai, & Yamazaki, 2013).

Traditional social norms and positive experience of caregiving
Studies that attempted to analyze the positive caregiving experience were rare.Where this was reported, positive experiences of caregiving were normally related to traditional social norms in the context of Chinese culture.Filial piety (where children reciprocate the care one's parents have given) impelled carers' care for the relative with schizophrenia (Poon, Joubert, & Harvey, 2013), which could be seen to be related to traditional family values.Because of this, CPSs obtained positive feedback about being involved in an ill family member's life.A study in Swaziland reported that CPSs obtained a sense of satisfaction from caregiving because they were actively involved in the life of the ill relative (Ntinda & Nkwanyana, 2017), and Gater et al. (2014) reported the most beneficial aspect of caregiving was the love that the CPSs shared with the person with their relative.Positive caregiving experiences were also strongly associated with kinship, especially within marriage and intimate partnerships (Jungbauer, Wittmund, Dietrich, & Angermeyer, 2004).

Discussion
The analysis of publications shows increasing attention to the topic of carer burden within the past few decades.This publication trend may be because there has been great attention paid to psychological and financial effects on lives of women who are expected to be the primary carers by feminists since the 1980s (Glasby & Tew, 2015;Graham, 1991;Hooyman & Gonyea, 1999).Additionally, changes in policy, mainly due to a shift to community-based mental health services, has led to more attention being paid to the needs of carers caring for ill relatives at home (Rahmani et al., 2019).The review also identifies a broad geographical distribution of publications.However, most articles focusing on the understandings of caregiving experience associated with CPSs were based in India, the United Kingdom, China, the United States of America, and Hong Kong; with four studies conducted in South America, which were fully focused on Chile.The findings demonstrate that quantitative research designs (n = 80) are most frequently employed to understand carer burden and how it impacts CPSs and families.This might result in a lack of knowledge about carers' subjective feelings about caregiving.Also, nine quantitative longitudinal research studies reported inconsistent findings within the aspects tested, such as carer burden, quality of life, and positive experience of caring throughout defined periods.Rhee and Rosenheck (2019) indicated that no change in family burden may have occurred because CPSs had acted in that capacity for an average of 13 years and so may have become accustomed to caring.
Based on the definitions of CPSs that have been given in the reviewed studies, they consistently defined that CPSs should be the person who is most intimately involved in the life of the care recipient and unselfishly provide supports, such as accompanying people with schizophrenia to the hospital and looking after their daily needs for at least 1 year.However, the living situation of CPSs was rarely discussed within studies.Only four studies mentioned the living situation and identified that the CPSs living with the care recipient.Accordingly, the condition of whether CPSs live with their relative should be considered in the future and this should be explicit within carer definitions.The findings from this study demonstrated that the proportion of female carer participants was higher than the proportion of male carer participants in the reviewed studies, which was consistent with the results of other scoping reviews regarding the characteristics of CPSs (Carter, Monaghan, & Santin, 2020;Halim, Hairi, & Yuen, 2020;Queluz et al., 2020).A total of 74 (70%) included studies show that the number of parent carers was more than other kinship carers, such as spouses and siblings.
The concept of carer burden has been well defined since the 1960s (Hoenig & Hamilton, 1966;Hooyman & Gonyea, 1999), which could explain why most reviewed literature did not re-define carer burden, meaning that objective and subjective burdens were universally adopted across studies.This review aimed to reveal both objective and subjective burdens experienced by CPSs, and findings from the thematic analysis demonstrate that issues around both types of burdens have been well researched.The findings from this review showed that financial burdens, disruption to carers' daily lives and family relationships, which are considered as an obvious burden in terms of objective burden, were greatly researched.However, the physical effects of caregiving might be seen as a burden that was less observed compared to other domains of objective burden or generally less intensive than the psychological effects (Schulz & Sherwood, 2008).A previous study has pointed out that relatively little notice has been paid to the physical effects on CPSs compared to psychiatric outcomes (Chang, Chiou, & Chen, 2009), which can partly be explained by a lack of academic interest in this area (Salvatore, Amelia, Marco, & Carmela, 2014).It is also clear that there has been a lack of research focusing on the impact on the physical health of CPSs because most instruments used in the reviewed studies were focused on measuring their mental health, such as the extent of their anxiety and depression.The only disruption to physical health mentioned in the articles review was disruptions to the sleeping patterns of CPSs due to the problematic behaviors of people with schizophrenia.Therefore, important knowledge on the physical impacts of caring is lacking.
Given the findings of this review, considerable subjective burdens can be observed when families are caring for a person with schizophrenia.The level of subjective burden was between mid and moderate among most CPSs in the reviewed studies, meaning that CPSs would experience high negative emotions due to caring for people with schizophrenia.This is consistent with those of Salvatore, Amelia, Marco, and Carmela (2014), who found that carers of people with mental health problems more generally have a higher emotional burden and lower physical burden compared to carers of people who are physically disabled, and of Schulz and Sherwood (2008), who reported that caring for a patient with dementia is more challenging than caring for a patient with exclusively physical disabilities.This review has highlighted that the subjective burden of CPSs would increase in some circumstances that occurred because of persons with schizophrenia, such as when the care recipients relapse into schizophrenia.Boydell et al. (2014) emphasized that timely access to relevant services for service users experiencing the first episode of psychosis might positively impact both the course of the illness for patients and also the experience of CPSs.In conclusion, understanding situations which may cause significant subjective burden for CPSs may lead to better assistance and services for .This review has thematically analyzed the caregiving experience of CPSs.Findings show that CPSs were likely to lack knowledge about schizophrenia and struggle to gain appropriate help from mental illness professionals.This result is consistent with Dixon, Stone, and Laing (2022) who evidenced frustration with mental health services by carers because they were dissatisfied with the support they received from mental health professionals.Compared to professional services, informal sources, such as friends, faith, and relatives, seem to be the main resources that carers frequently obtained support from and were regarded as more useful resources than services provided by professionals by most carers.From the literature, on the other hand, social support is a significant mediator or moderator to carer burden of carers caring for a family member with a cognitive impairment (Chien, Chan, & Morrissey, 2007;Chou, 2000;Ribé et al., 2018) and some studies found that social support as a coping strategy was commonly used by carers (Chadda, Singh, & Ganguly, 2007;Verma, Grover, & Chakrabarti, 2021) yet merely 20% of reviewed studies referred to the social services involvement or the provision of other support systems (such as charitable organizations).There has been a lack of discussion in previous literature on the experience CPSs of accessing/utilizing social supports and what CPSs can benefit from these services.

Limitations
This scoping review has a few limitations.First, the inclusion and exclusion criteria, as well as the choice of search databases, might limit the range and volume of the reviewed literature.Also, the hand search may not have identified all articles which were in scope with the review.Second, the exclusion of non-English publications may have limited the geographical range and number of cultural perspectives presented.For example, the articles regarding particular care systems, such as the long-term care insurance in Japan and Germany, might be published using a language other than English and thus are worth future research.Third, the ways of reporting the type and level of burden were different across time and place, which cause the findings of both objective and subjective burden to be unable to be presented consistently, either temporally or spatially.Fourth, although this review extracted variables of carers' socio-demographic (see Appendix 1) to allow us to gain a more complete picture of CRSs, the types of variables are limited to the data collection process of the included studies and the information presented in the reviewed articles.Despite these limitations, this review sought to gain existing knowledge about CPSs and enrich the possibility of future research into this important topic area.

Future research suggestions
The findings of this review indicate that further studies could consider employing longitudinal designs to address the state versus process of carer burden for caring for people with schizophrenia.Such studies could, for example, explore the change of carer burden in different courses of schizophrenia.Exploring the literature published in languages other than English would be useful for academics to fully understand this topic.In terms of research topics, it could be beneficial to investigate positive perspectives of CPSs while looking after their ill relatives because studies demonstrated that CPSs did enjoy the caregiving process and find it could be a source of positive feelings in a person's life.Future research would benefit from an investigation into the effectiveness of support services for CPSs, which will enhance the understanding of which care services will be helpful for families with schizophrenia.

Conclusion
The findings from this review shed light on the characteristics and distribution of the literature, identifying definitions of CPSs, the dimensions of both objective and subjective burdens, and key aspects of the caregiving experience.In line with the carer burden literature, caring for people with schizophrenia brings significant disruption to carers' social life and family relationship within objective burden.Meanwhile, subjective burden might be related to different episodes of psychosis in ill relatives and be because of a lack of support from professional departments.Notably, social environmental factors were rarely taken into account in how they influence carer burden in the reviewed studies.The review recognized that efforts to investigate and develop social support services for CPSs need to be paid more attention, which therefore requires a focus on the effectiveness of social services that might reduce carer burden and provide effective interventions for CPS.

Notes
1. Levac et al (Levac, Colquhoun, & O'Brien, 2010).identified six stages of scoping review which were developed based on Arksey and O' Malley methodological framework.The sixth stage is consultation, providing opportunities for stakeholder to suggest additional reference and insights beyond those in the literature, which has not been used in this scoping review.2. The qualitative rigor includes four components.They are credibility, transferability, dependability, and confirmability.

Figure 1 .
Figure 1.PRISMA flow chart of review study selection process.

Table 1 .
Database search terms.

Table 2 .
Inclusion and exclusion criteria.