The first finding in achieving the aim of the study is that the analyzed articles highlight diverse SM/MV groups. The diversity of SM or MV groups regarding mental health can be explained through a combination of sociological, psychological, and biomedical perspectives. Based on a non-systematic narrative review, Souza et al. [47] found a statistically significant independent association between poorer mental health and low income, marital status or lack of a partner, lack of emotional/social support, female gender, low education, low socioeconomic status, unemployment, financial stress, perceived discrimination, negative subjective health status, loneliness, low subjective social status, poorer housing conditions, older age, and negative life events. The stigma surrounding mental health can disproportionately affect certain groups [6, 11, 12, 13, 14]. Biologically, different groups have varying susceptibilities to mental health disorders due to genetic, neurobiological, or physiological factors [111]. Individual psychological factors such as resilience, coping mechanisms, and personal history (like trauma) play a role in mental health [112]. Healthcare system limitations are also key macro determinations, including differences in access to mental health services, the quality of care received, and healthcare provider biases or lack of cultural competence [113]. Some groups carry the burden of historical or societal trauma (e.g., indigenous populations, refugees, or communities that have experienced systemic racism), which can have profound and lasting impacts on mental health. As laws and policies can protect or marginalize certain groups, they are also key determinants. For example, policies that do not recognize the specific mental health needs of LGBTQ + individuals can lead to inadequate support and increased vulnerability [114].
The VulnerABLE project focused on nine target groups with poor health and/or face barriers to accessing health care. These included the following: (1) families who are in a vulnerable situation (e.g., single parents with young children); (2) people with physical, mental or learning disabilities or poor mental health; (3) the working poor; (4) older people who are in a vulnerable situation; (5) people in unstable housing conditions (e.g., the homeless); (6) prisoners (or former prisoners in a precarious situation); (7) people living in rural/isolated areas who are in a precarious situation; (8) long-term unemployed/inactive people (not in education, training or employment); and (9) survivors of domestic violence and intimate partner violence (European Commission, 2017[110]). The most common groups/individuals with MV are (NIJZ, 2020, p. 43)[90]: (1) older residents; (2) immigrants, foreign language speakers; (3) people with various forms of disabilities; (4) socio-economically disadvantaged individuals and families; (5) children and adolescents with various vulnerabilities; (6) the unemployed; (7) the uninsured (people without statutory health insurance and/or without supplementary insurance); (8) Roma; (9) people with mental disorders; (10) users of illegal drugs; (11) homeless people; (12) alcohol addicts; (13) victims of domestic violence; (14) prisoners and ex-prisoners; (15) women with different protection needs; (16) people with long-term illnesses; (17) people living in geographically remote areas; (18) victims of economic violence; (19) homosexuals; and (20) sex workers. When we supplemented these highlighted lists with other references to SM/MV from other articles, we got a comprehensive list of 18 sets of SM/MV groups that were identified in connection with QIHC in the field of MHC. It became evident that it would not be useful to separate the SM/MV groups for our research, as the risk factors overlap and complement one another within the classification or use of individual SM/MV designations. It must be considered that if vulnerabilities have already been demonstrated, new ones may be added to the individual groups with vulnerabilities given the already perceived risks [2, 47].
The systematic literature review also identified that the range of countermeasures is very comprehensive, but by no means definitive. The eight recognized domains and a total of 52 measures can be helpful at all levels. Adapting the individual measures to the national and SM/MV context is essential. The countermeasures need to be addressed comprehensively as part of integrated mental health and social care for SM/MV adults and promote culturally competent ethical attitudes among health professionals and in society at large. The results showed that the countermeasures within each area are repeated/added independently of the SM/MV group. This was also confirmed in a detailed review where we compared measures for groups as diverse as lesbian, gay, bisexual and transgender, and Gypsy, Roma, and Traveler communities. The Roma are considered the largest and most marginalized ethnic minority in Europe, and although exact numbers are not known, they are estimated to number between ten and twelve million people [67]. The countermeasures are not mutually exclusive but complement one another, leading to QIHC and quality MHC.
The implemented or proposed countermeasures/interventions to reduce the prevalence of mental disorders in the population and in SM/MV groups targeting different ages are: early childhood with impact on later years – violence prevention [20]), and establishment and expansion of the implementation of different programs to increase resilience at all ages [80, 104].
The countermeasures "establishing a working group to address MH programs for people on the margins of society" and "advocating for an increase in funding for MH promotion" could otherwise also be categorized as "inclusion and advocacy in administration and governance". From the cause-effect aspect of risk management, it can be concluded that the countermeasure "monitoring and reducing the incidence of stigma towards SM/MV groups and mental health disorders in the population" influences the lower incidence of mental health disorders in SM/MV adults [101]. The countermeasures/interventions implemented or proposed to improve the accessibility of services and their appropriateness focus primarily on how barriers in communication between providers and users can be removed, e.g., with mediators, in order to achieve equal access for all population groups [35, 55]. The countermeasures/interventions reveal efforts to take a more integrated approach and create a network of services. They emphasize the importance of communication between service providers and horizontal and vertical equity in terms of the frequency of visits to health services [77, 81]. The Roma are one of the SM/MV groups that have less access to prevention programs on the one hand but see a doctor more frequently on the other [75, 105]. The NIJZ [90] emphasizes that "four dimensions of service accessibility must be considered in efforts to improve accessibility: non-discrimination, physical accessibility, affordability and information accessibility". The countermeasure/intervention of "providing a supportive work environment to mitigate burnout" also targets the healthcare workforce and the responsibility of healthcare provider management [77, 107].
The categories of countermeasures "person-centred care", "quality of health care for people with MH disorders", and "ethics and morality for equity, equality, and justice" include a whole range of countermeasures that complement the category "development of specific competencies/skills".
Under the category "person-centered care", all of the measures listed point to the importance of holistic health care that responds to the patient's needs. For example, the measures "adapting the provision and delivery of services to the factors of the social context (taboos, prejudice, discrimination, social integration, social support, norms) [62, 63, 70, 97, 101] or "the MH of MV people must be understood in the context of other important personal identities: sexual, ethnic, cultural, and religious" [91]) testify to the need for an individualized approach of the health professional towards the user, in response to the real needs of adults with a mental health disorder. Stigma is inherently a cross-sectoral phenomenon and therefore efforts to reduce stigma and its harmful effects require a multi-level approach [86]. All authors focusing on the implementation of countermeasures/interventions to reduce stigma [38, 50, 79, 107] agree that countermeasures and efforts are necessary; stigma will not disappear by itself. The target groups for the countermeasures are management [95], healthcare workers [59, 82, 89, 103, 106], students [82], educators [103], SM/MV adults and their families [52], as well as the general population [86]. Thus, educational programs alone are often ineffective in reducing stigmatizing attitudes in members of the public, and the little resulting stigma reduction that occurs may be short-lived and superficial. Future research on multi-level stigma interventions is therefore needed to explore a wider range of stigma-reduction strategies and to utilize evidence-based strategies that prior research has shown to be effective in reducing stigma [86]. "Peer support workers" [101] is a countermeasure that is gaining traction in MHC for SM/MV adults and contributes to the quality of services.
Most countermeasures fall under the category of quality of health care for people with MH disorders. These include efforts to improve inclusion and health literacy [48], the provision of culturally competent care, and research findings suggesting that staff working in mental health settings share some societal biases about mental disorders. This can lead to stigmatizing behavior towards people with mental disorders, which undermines the quality of their care [12].
Countermeasures in the categories "evidence-based practice" and "inclusion and advocacy in administration and governance" go hand in hand. "Inclusion and advocacy in administration and governance" cannot occur without data. The range of proposed research is rich. We highlight opportunities for new research and program development in multi-level stigma interventions organized around several key domains (e.g., measurement, mechanisms of change, implementation). This list is not exhaustive but is meant to underscore some of the most important areas of inquiry needed to advance the knowledge base in this incipient field. There are still many opportunities for improvement. It is also necessary to pay attention to the available human and financial resources [18, 71]. It all starts with the development of specific competencies and critical self-assessment, promoting (self-)acceptance of personal identity [61, 63, 70, 97].
Strengths and limitations
This study establishes a foundation for future investigations by identifying existing gaps in the current literature. Although extensive efforts were made to ensure comprehensive coverage, the possibility remains that some pertinent studies may have been inadvertently excluded. Our methodology involved integrating studies identified through search terms derived from prior reviews, coupled with rigorously defined inclusion and exclusion criteria. This research attempts to address a complex concept through a novel approach. However, the limitation to English-language studies inherently restricts the scope of included literature, predominantly favouring studies from high-income countries. In our analysis, we did not distinguish between SM and MV groups, opting instead to categorize findings as relevant to both cohorts collectively. While our results indicate the presence of targeted interventions for specific SM/MV groups, the review prioritized the evaluation of comparability and applicability across different contexts. This approach acknowledges the nuanced differences among these groups while simultaneously exploring commonalities that could inform broader, transferable strategies in public health interventions.
For future research, it is recommended that the spectrum of these countermeasures be refined and augmented in at least two key aspects: (1) in terms of content, through the inclusion of additional SM/MV groups and the implementation or proposal of new countermeasures; and (2) from the perspective of evaluating the impact of these countermeasures on the quality of MHC, considering the viewpoints of various stakeholders involved. This approach not only aims to broaden the scope of existing interventions but also seeks to enhance the effectiveness and applicability of these strategies in improving mental healthcare outcomes across diverse populations.