Introduction

Mental disorders such as depression and anxiety are prevalent, with nationally representative studies showing that one-fifth of Australians experience a mental disorder each year [5]. More recent estimates derived from a similar survey during the period of the COVID-19 pandemic were 21.5% [11]. Mental illness can reduce the quality of life, and increase the likelihood of communicable and non-communicable diseases [116, 137], and is among the costliest burdens in developed countries [22, 34, 80]. The National Mental Health Commission [96] stated that the annual cost of mental ill-health in Australia was around $4000 per person or $60 billion. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 reported that mental disorders rank the seventh leading cause of disability-adjusted life years and the second leading cause of years lived with disability [48]. Helliwell et al. [56] indicated that chronic mental illness was a key determinant of unhappiness, and it triggered more pain than physical illness. Mental health issues can have a spillover effect on all areas of life, poor mental health conditions might lead to lower educational achievements and work performance, substance abuse, and violence [102]. In Australia, despite considerable additional investment in the provision of mental health services research suggests that the rate of psychological distress at the population level has been increasing [38], this has been argued to reflect that people who most need mental health treatment are not accessing services. Insufficient numbers of mental health services and mental healthcare professionals and inadequate health literacy have been reported as the pivotal determinants of poor mental health [18]. Previous studies have reported large treatment gaps in mental health services; finding only 42–44% of individuals with mental illness seek help from any medical or professional service provider [85, 112] and this active proportion was much lower in low and middle-income countries [32, 114, 130].

Several studies have investigated factors associated with high and low rates of mental health service use and identified potential barriers to accessing mental health service use. Demographic, social, and structural factors have been associated with low rates of mental health service use. Structural barriers include the availability of mental health services and high treatment costs, social barriers to treatment access include stigma around mental health [125], fear of being perceived as weak or stigmatized [79], lack of awareness of mental disorders, and cultural stigma [17].

Existing studies that have systematically reviewed and evaluated the literature examining mental health service use have largely been constrained to specific population groups such as military service members [63] and immigrants [33], children and adolescents [35], young adults [76], and help-seeking among Filipinos in the Philippines [93]. These systematic reviews emphasize mental health service use by specific age groups or sub-groups, and the findings might not represent the patterns and barriers to mental health service use in the general population. One paper has reviewed mental health service use in the general adult population. Roberts et al. [112] found that need factors (e.g. health status, disability, duration of symptoms) were the strongest determinants of health service use for those with mental disorders.

The study results from Roberts et al. [112] were retrieved in 2016, and the current study seeks to build on this prior review with more recent research data by identifying publications since 2012 on mental health service use with a focus on high-income countries. This is in the context of ongoing community discussion and reform of the design and delivery of mental health services in Australia [140], and the need for current evidence to inform this discussion in Australia and other high-income countries. This systematic review aims to investigate factors associated with mental health service use among people with mental disorders and summarize the major barriers to mental health treatment. The specific objectives are (1) to identify factors associated with mental health service use among people with mental disorders in high-income countries, and (2) to identify commonly reported barriers to mental health service use.

Methodology

Selection procedures

Our review adhered to PRISMA guidelines to present the results. We utilized PubMed, Scopus, and the Web of Science to search for articles describing the facilitators and barriers to mental health service use among people with mental illness from January 2012 up to August 2023. There were no specific factors that were of interest as part of conducting this systematic review, instead, the review had a broad focus intending to identify factors shown to be associated with mental health service use in the recent literature. The keywords used in our search of electronic databases were related to mental disorders and mental health service use. The full search terms and strategies were shown in Supplementary Table 1. We uploaded the search results to Covidence for deduplication and screening. After eliminating duplicates, the first author retrieved the title abstract and full-text articles for all eligible papers. Then each title and abstract were screened by two independent reviewers, to select those that would progress to full-text review. Subsequently, the two reviewers screened the full text of all the selected papers and conducted the data extraction for those that met the eligibility criteria. There were discrepancies in 12% of the papers reviewed, and all conflicts were resolved through discussion and agreed on by at least three authors.

Selection criteria

Inclusion and exclusion criteria

In this systematic review, the scope was restricted to studies that draw samples from the general population, and the participants were either diagnosed with mental disorders or screened positive using a standardized scale. Case-control studies and cohort studies were considered for inclusion. The applied inclusion and exclusion criteria are listed in Table 1.

Table 1 Inclusion and exclusion criteria

Data extraction

After the full-text screening, details from all eligible studies were extracted by field into a data extraction table with thematic headings. The descriptive data includes the study title, author, publication year, geographic location, sample size, population details (gender, age), type of study design, mental disorder type (medical diagnosis or using scales) and quality grade (e.g. good, fair, and poor).

Quality assessment

The Newcastle Ottawa Scale [136] was used to evaluate the study quality for all eligible papers. We assessed the cross-sectional and cohort studies using separate assessment forms and graded each study as good, fair, or poor. The quality grade for each study was included in the data extraction table. The first author conducted the quality assessment using the Newcastle Ottawa Scale for cohort studies and the adapted scale for cross-sectional studies.

Results

The search process is summarized in Fig. 1. The initial search from PubMed, Scopus, and the Web of Science yielded 3230 articles: 2366 remained after removing duplicates; 2129 studies were considered not relevant; and 237 studies remained following title and abstract screening. In total, 40 studies met the inclusion criteria. Of these, four were cohort studies while thirty-six were cross-sectional studies. Ten studies (25.0%) were conducted in Canada, and nine (22.5%) were from the United States. Three studies used data from Germany (7.5%). Two studies each reported data from Australia, Denmark, Sweden, Singapore, or South Korea (5.0% of studies for each country). A single study was included with data from either the United Kingdom, Italy, Israel, Portugal, Switzerland, Chile, New Zealand, or reported pooled multinational data from six European countries (each country/ study representing 2.5% of the total sample of studies) (Table 2).

Fig. 1
figure 1

Flowchart for selections of studies

Table 2 Basic study information

Study characteristics

As shown in Tables 23 and 4, the sample size of studies varies; a cross-sectional study from Canada had the largest sample which contained over seven million participants [39], while the smallest sample size was 362 [100]. Sixteen studies (40.0%) used DSM-IV diagnoses [4] to measure mental disorders, twelve studies (30.0%) applied the International Classification of Disease [138], and six studies used (15.0%) the Kessler Psychological Distress Scale [69]. Only three studies (7.5%) had a hospital diagnosis of mental disorders, while three studies (7.5%) used the Patient Health Questionnaire [72] to define mental disorders.

Table 3 Mental disorder and mental health service type
Table 4 Study quality and outcomes

Twenty-seven studies (67.5%) analyzed the rate of mental health service use over the last 12 months, six studies (15.0%) focused on lifetime service use, and three studies (7.5%) assessed both 12-month and lifetime mental health service use. A few studies examined other time frames, with single studies investigating mental health service use over the past 3 months, 5 years, and 7 years, and one included study considered mental health service use during the 24 months before and after a sibling’s death.

Twenty of the forty studies were classified as good quality (50.0%), seventeen as fair (42.5%), and three as poor quality (7.5%).

Overview of samples and factors investigated

The included studies examined a range of different factors associated with mental health service use. These included gender, age, marital status, ethnic groups, alcohol and drug abuse, education and income level, employment status, symptom severity, and residential location. The review identified service utilization factors related to socio-demographics, differences in utilization across countries, emerging socio-demographic factors and contexts, as well as structural and attitudinal barriers. These are described in further detail below.

Socio-demographic characteristics

Gender

Fifteen studies analyzed the association between gender and mental health service use, with fourteen studies reporting that mental health service use was more frequent among females with mental disorders than males [2, 37, 42, 43, 47, 54, 66, 67, 90, 103, 119, 123, 128, 130]. A South Korean study concluded that gender was not associated with mental health service use [100], which might be due to the small sample size of 362 participants in the study.

Age

Fourteen studies investigated age in association with mental health service use. Nine studies concluded that mental health service use was lower among young and old adult groups, with middle-aged persons with a mental disorder being most likely to access treatment from a mental health professional [26, 42, 43, 47, 54, 66, 67, 123, 130]. Forslund et al. [43] reported that mental health service use for women in Sweden peaked in the 45-to-64-year age group, while amongst males, mental health service use was stable across the lifespan. In contrast, two articles from New Zealand and Singapore each reported that young adults were the age group most likely to access services [28, 119]. Reich et al. [103] concluded that age was unrelated to mental health service use when considered for the whole population, but sex-specific analyses reported that mental health service use was higher in older than younger females, while the opposite pattern was observed for males. A Canadian study using community health survey data also observed no significant age-related differences in mental health service use [104].

Marital status

There was mixed evidence concerning marital status. Studies from the United States and Germany concluded that participants who were married or cohabiting had lower rates of mental health service use [26, 90], while Silvia et al. [120] found that mental health service use was higher among married participants in Portugal. Shafie et al. [119] reported being widowed was associated with lower rates of mental health service use in Singapore.

Ethnic groups

Eight studies examined the relationship between ethnic background and mental healthcare service use. Non-Hispanic White respondents were more likely to use mental health services in Canada and the United States [24, 26, 30, 130, 139], while Asians showed lower rates of mental health service use [28, 139]. Chow & Mulder [28] investigated mental health service use among Asians, Europeans, Maori, and Pacific peoples in New Zealand. They concluded that Maori had the highest rate of mental health service use compared with other ethnic groups. De Luca et al. [30] reported that mental health service use was lower among ethnic minority non-veterans compared to veterans in the United States, especially for those with Black or Hispanic backgrounds. In contrast, a study conducted in the UK found that mental health service use did not vary by ethnicity, with no difference between white and non-white persons [54].

Alcohol and drug abuse

Two studies reported risky alcohol use was negatively associated with mental health service use [26, 132]. However, within the time frame of the current review, there was insufficient published evidence on the impact of drug abuse on mental health service use among people with mental disorders. Choi, Diana & Nathan [26] found that drug abuse can lead to lower rates of mental health service use in the United States. In contrast, Werlen et al. [132] reported that risky use of (non-prescribed) prescription medications was associated with higher rates of mental health service use in Switzerland.

Education, income, and employment status

Four studies analyzed the relationship between education level, income, and mental health service use. Higher levels of educational attainment [26, 120] and higher income [26] were generally reported to be associated with an increased likelihood of mental health service use. However, Reich et al. [103] observed that in Germany, high education and perceived middle or high social class were associated with reduced mental health service use. One paper reported no significant difference in mental health service use in South Korea, possibly due to the small number of people accessing mental healthcare services [100].

Three studies reported that compared to those who are unemployed, those in work were less likely to use mental health services [26, 90, 119]. This outcome aligned with a Canadian study consisting of immigrants and general populations, Islam et al. [66] concluded that immigrants who were currently unemployed had higher odds of seeking treatment than those who were employed. However, an Italian [123] and a South Korean study [100] found that employment status was not related to mental health service use.

Symptom severity

Ten studies investigated the association between symptom severity and mental health service use and ten papers concluded that participants with moderate or serious psychological symptoms were more likely to use mental health services compared to those with mild symptoms [23, 27, 66, 103, 120, 123, 130, 139]. Other studies showed that study participants who viewed their mental health as poor [42], who were diagnosed with more than one mental disorder [103], and those who recognized their own need for mental health treatment [54, 139] were more likely to receive mental health services.

Residential location

Three studies investigated the association between residential location and mental health service use. Volkert et al. [128] concluded that the rates of mental health service use in Germany were significantly lower among those living in Canterbury than those living in Hamburg. A Canadian study found individuals living in neighborhoods where renters outnumber homeowners were less likely to access mental health services [42]. In the United States, for participants with low or moderate mental illness, mental health service use was lower for those residing closer to clinics [46].

Immigrants & refugees

The reviewed research found that non-refugee immigrants had slightly higher rates of mental health service use than refugees [10]. Other research found that long-term residents were more likely to access services than immigrants regardless of their origin [31, 134]. For example, Italian citizens were found to have higher rates of mental health service use compared to immigrants, especially for affective disorders [123]. In Canada, immigrants from West and Central Africa were more likely to access mental health services compared to immigrants from East Asia and the Pacific [31]. Research from Chile found that the rates of mental health service use were similar for immigrants and non-immigrants [40]. Although, a positive association between the severity of symptoms and rates of mental health service use was only observed among immigrants [40]. Whitley et al. [134] found that immigrants born in Asia or Africa had lower rates of mental health service use, but higher rates of service satisfaction scores compared to immigrants from other countries.

Emerging areas

Our literature review identified several areas in which only a small number of studies were found. We briefly describe them here as these may reflect emerging areas of research interest. Few published articles examined mental health treatment among participants with mental disorders together with chronic physical health conditions, and we only included the papers in this systematic review if they contained a healthy comparison group. We identified two papers that focused on survivors of adolescent and young adult cancer [68] and participants with physical health problems [110]. Both studies reported that participants with other chronic conditions reported higher rates of mental health service use than the general population [68, 110].

Two studies compared treatment seeking among people experiencing stressful life events. Erlangsen et al. [39] investigated the impact of spousal suicide, and Gazibara et al. [45] examined the effect of a sibling’s death on mental health service use. People bereaved by relatives’ deaths were more likely to use mental health services than the general population [39, 45]. The peak effect was observed in the first 3 months after the death for both genders, while evidence of an increase in mental health service use was evident up to 24 months before a sibling’s death and remained evident for at least 24 months after the death [45].

One paper studied the impact of the COVID-19 pandemic lockdown on mental health service use. An Israeli study concluded that compared to 2018 and 2019, adults reported they were reluctant to receive treatment during the pandemic lockdown and observed a decrease in mental health service use [13].

Structural and attitudinal barriers

In addition to the research considering a range of population characteristics (e.g. male, younger, or older age), several papers examined how attitudinal and structural factors were associated with mental health service use. The most frequently reported of these factors were cost [23, 46, 68, 120], lack of transportation [46, 83], inadequate services/ lack of availability [23, 46, 83, 128], poor understanding of mental disorders and what services were available [10, 11, 22, 83, 100, 105, 120], language difficulties [10], and stigma-related barriers [83, 100, 103, 105, 128]. Cultural issues and personal beliefs may influence the understanding of mental disorders and prevent people from using mental health services due to mistrust or fear of treatment [100, 128]. The review also observed some unique barriers to different population groups. Choi, Diana & Nathan [26] mentioned that lack of readiness and treatment cost were the biggest difficulties for older adults, while young participants were more concerned about stigma. Females also reported childcare as a factor limiting their ability to use mental health services, while the evidence reviewed argued that males prefer to solve mental health issues on their own, with internal control beliefs and lack of social support likely reducing their use of mental health services [37, 103].

Discussion

Summary of evidence

This systematic review investigated mental health service use among people with mental disorders and identified the factors associated with service use in high-income countries.

Most studies found that females with mental health conditions were more likely to use mental health services than males. The relationship between age and mental health service use was bell-shaped, with middle-aged participants having higher rates of mental health service use than other age groups. Possible explanations included that the elderly might be reluctant to disclose mental health symptoms, they might attribute their mental health symptoms to increasing age [20], and they may prefer to self-manage instead of seeking help from health professionals [44]. Caucasian ethnicity and higher household income were also associated with higher rates of mental health service use. Greater use of mental health services was observed in participants with severe mental symptoms, including among veterans [19, 37, 92]. Two studies also concluded that compared to other cultural groups, Asian respondents were more likely to receive treatment when problems were severe or had disabling effects [86, 97]. There was mixed evidence regarding employment status, although some studies found employment to be negatively related to receiving treatment [26, 90], and unemployed people are more likely to seek help [119]. There was inconsistent evidence for the association between marital status and service utilization. This contradictory evidence on marital status might be attributed to a lack of specification, some papers categorize it as married and non-married [26, 71, 131], while others further differentiate between those who were widowed, separated, and divorced [90, 119].

Immigrants

A number of studies showed that immigrants can face unique stressors owing to their experience of migration, which may exacerbate or be the source of their mental health issues, and impact the use of mental health services [1, 8]. These include separation from families, support networks, linguistic and cultural barriers [9, 113].

Due to the increased number of international migrants, immigrants’ mental health status and healthcare use has drawn growing attention [7, 77, 99]. Kirmayer et al. [70] and Helman [57] found that culture might be associated with people’s attitudes and understanding of mental health, influencing help-seeking behaviors. In general, the current results showed that immigrants and refugees were less likely to use mental health services than their native-born counterparts, and this finding was consistent with previous studies [75, 82, 127]. For immigrants, the length of stay in the host country was closely related to rates of mental health service use, which was argued to reflect increasing familiarity with the host culture and language proficiency [1, 59].

Emerging areas

Both mental disorders and chronic diseases contribute significantly to the global burden of disease. Prior studies have shown that people with chronic disease have a higher chance of experiencing psychological distress [6, 14, 68, 73], and vice versa [49, 74]. Hendrie et al. [58] concluded that respondents with chronic diseases were more likely to attend mental healthcare and reported higher costs. Negative experiences and stressful consequences related to chronic disease might contribute to the increased potential for mental illness but more opportunities to seek help from health professionals [60, 108, 135]. People with chronic diseases and mental health problems might experience more long-term pain and limitations in their daily lives, and these stressors can exacerbate their health conditions, and impact their attitude toward seeking help.

The COVID-19 pandemic had a major impact on mental health service use worldwide, the hospital admission and consultation rate decreased dramatically during the first pandemic year [118]. This reduction in service access might be a side effect of social distancing measures taken as mitigation measures, reducing both inciting incidents and physical access to services.

Financial difficulty, service availability, and stigma were frequently identified in the literature as structural and attitudinal factors associated with lower rates of mental health service use. These factors were associated with the different rates of mental health service use for different ethnicities. For example, Asian people were less likely than other groups to identify cost as a factor limiting their use of mental health services, with a major barrier for Asian people being stigma and cultural factors [139].

Limitations

This systematic review employed a broad search strategy with broad search terms to capture relevant articles. Rather than emphasizing a particular mental disorder, this review focused on the rates of mental health service use among adults aged 18 years or older who were experiencing a common mental disorder. However, this review still contained limitations. First was the potential for selection bias. Although we used various search terms for mental health service use and mental disorder, it is possible that the service use was not the primary research question for some papers, or that the relevant service use outcome was not statistically significant- in these cases, if the information was not reported in the abstract, relevant papers might have been missed. It is also important to note that this systematic review includes studies conducted in different countries and that the mental health systems and opportunities for access vary among countries. We only searched for full-text peer-reviewed articles published in English. Grey literature and papers published in other languages were excluded from the search. Most of the included literature used self-reported data to measure service access, and these data can be liable to recall bias. Studies using administrative data were also included in the systematic review, and we note that although they have large datasets, compared to survey data, there is often a lack of adequate control variables included to minimize possible confounding influences.

Future research

There is a need for more published articles on several aspects that may influence the service utilization among people with mental disorders, including the impact of residential or neighborhood areas, and household income across various income groups. These aspects are important population characteristics that require further research to inform the targeting and type of support (e.g. low-cost, accessible). Additionally, there was a lack of longitudinal research on mental health service use, future studies could use the data to identify changes over time and relate events to specific exposures (e.g. Covid-19 pandemic). Future studies can investigate the cost of mental health treatment in detailed aspects, (e.g. publicly funded mental health services, community-based support for free or low-cost mental health services). Overall, there was a lack of studies for ethnic minorities, given ethnic minority groups were more vulnerable to mental disorders but with less mental health service use. Future research can expand gender identity representation in data collection and move beyond the binary genders. People with non-binary gender identities can face greater challenges and disadvantages in mental health and mental health service use.

Conclusion

This review identified that middle-aged, female gender, Caucasian ethnicity, and severity of mental disorder symptoms were factors consistently associated with higher rates of mental health service use among people with a mental disorder. In comparison, the influence of employment and marital status on mental health service use was unclear due to the limited number of published studies and/ or mixed results. Financial difficulty, stigma, lack of transportation, and inadequate mental health services were the structural barriers most consistently identified as being associated with lower rates of mental health service use. Finally, ethnicity and immigrant status were also associated with differences in understanding of mental health (i.e. mental health literacy), effectiveness of mental health treatments, as well as language difficulties. The insights gained through this review on the factors associated with mental health service use can help clinicians and policymakers to identify and provide more targeted support for those least likely to access services, and this in turn may contribute to reducing inequalities in not only mental health service use but also the burden of mental disorders.