Assessing service use for mental health by Indigenous populations in Australia, Canada, New Zealand and the United States of America: a rapid review of population surveys

There exists a strong consensus that Indigenous populations of Australia, Canada, New Zealand and the United States of America experience mental health inequities relative to the non-Indigenous population. To address this disparity and optimally allocate resources, health planners require population-level information about how many Indigenous people are using mental health services, the types of interventions they receive, the extent to which these interventions align with best available evidence, their unmet needs for care and the barriers to care [1]. A content review of existing service use modules in Indigenous surveys is required to determine whether the information needed to guide service development is being collected and to inform future survey design.

While wary of the danger of pathologising Indigenous communities [2], some epidemiological surveys and anecdotal evidence suggests that Indigenous populations in these four countries experience a higher disability and mortality burden from mental disorders and substance abuse than their non-Indigenous counterparts [3‐7]. However, findings are not consistent across studies; this may reflect methodological differences as well as within and between-group diversity across Indigenous populations. For instance, an epidemiological study in the United States, which looked at mental disorders among the Southwest and Northern Plains Native Americans, found that neither group experienced a higher overall burden of mental disorders as compared to the general United States population, yet both experienced disparities (to different degrees) in particular disorders, such as lifetime alcohol dependence and lifetime post-traumatic stress disorder [8]. The disparities exist despite these countries having well-established mental health service systems that offer a range of primary and specialised mental health services delivered by private, public and non-government providers. In addition to mainstream mental health services, each of these countries funds public programmes to deliver mental health services specifically for Indigenous people such as the Indian Health Service in the United States [9] and the National Aboriginal Community Controlled Health Organisation in Australia [10]. Table 1 provides a summary of the health service systems in the four countries.

The higher Indigenous burden likely results, at least in part, from inadequate treatment, unmet needs, and barriers to receiving appropriate and effective mental healthcare. There is evidence from epidemiological studies that Indigenous people diagnosed with a mental disorder use mental health services at different rates than other ethnic groups [6, 8]. Of Māori people with any mental disorder, only 32.5% visited services for mental health purposes, compared to 41.1% of other ethnic groups [6]. In one Native American tribe, women with any mental disorder made fewer visits for mental health to both specialty (30.8%) and general medical providers (22.6%) than their general population counterparts (33.8% and 42.7%, respectively) [8]. The hospitalisation rate for mental disorders in Australian Indigenous people is about double that of other Australians [11]. This situation is not unique to mental health; Indigenous people have lower overall health service utilisation rates than other ethnic groups and higher hospitalisation rates for any reason [12‐16]. Many factors can explain high rates of hospitalisation in a population, including a higher prevalence of illness as well as poorer access to, and availability of, other medical services [11].

Our understanding of the rates and characteristics of mental health service use in the general population has become increasingly sophisticated during the past 30 years. The definition of service use has also been debated and is evolving; with the focus shifting from the types and volume of services received, toward a multi-dimensional approach that encompasses quality of care, person-centeredness, comprehensiveness, integration, continuity, accessibility and cost of healthcare [17]. WHO’s World Mental Health (WMH) survey initiative represents an unprecedented effort to standardise and systematically examine mental health treatment across countries. The WMH survey initiative and other epidemiological surveys have increasingly focused on describing the frequency and volume of evidence-based treatments being delivered, and on identifying unmet needs for care and barriers to care [18]. These advances have enabled the quality of care being delivered to be estimated and individual treatment preferences to be identified, in turn highlighting possible service system deficiencies. For example, by comparing actual treatment delivered with recommendations from evidence-based treatment guidelines, epidemiological survey data has revealed disparities in rates of ‘minimally adequate treatment’ received by different racial or ethnic subpopulations [19‐21]. In the United States, one study showed that African Americans with major depressive disorder had significantly lower odds of receiving guideline-concordant treatment for depression than Whites [19]. Latinos with probable mental illness are also less likely than Whites to have received minimally adequate care in the United States [21]. Notably, however, rates of minimally adequate treatment for Indigenous people have not been reported.

Survey design factors account, in part, for limitations in the available information about service use for mental health by Indigenous populations. General population surveys rarely capture a large enough number of Indigenous respondents to draw conclusions about the extent and nature of their service use for mental health [22], although there are exceptions [23]. Even if they did include samples of sufficient size, question content may not acknowledge specialty Indigenous health services and interventions available or relevant for Indigenous people, such as traditional healers and culture-based interventions [22]. While some reports from Indigenous surveys have described aspects of service utilisation, these vary widely in scope and there is limited standardisation of the aspects of service use ascertained. Collectively, these limitations in available information hinder population-level planning for evidence-based service development for Indigenous people.

The aim of this study was to review the service use questions in Indigenous mental health population surveys to determine whether the information needed to guide service development is being collected. First, we asked ‘how many epidemiological surveys have measured service use for mental health among Indigenous populations?’ Second, ‘what elements of service use have these surveys included, and how do they compare with each other and with general population mental health surveys?’ Using this information, we then considered how service use questions in surveys of Indigenous people might best be asked in order to (1) achieve the specificity required for Indigenous contexts and (2) maintain the thoroughness of general population mental health surveys.