Background: Compared to heterosexual individuals, sexual minorities (e.g., those identifying as gay, lesbian, or bisexual) are at higher risk of several mental health problems, including suicidality, substance abuse, depression, and anxiety. Research has attributed much of these elevated risks to unique and chronic stress experiences, so-called minority stress, relating to the stigma and prejudice that many sexual minorities face. Less is known about how sexual minority stigma may function as a multilevel socio-ecological system that includes stigma-related risk factors at various levels, such as the structural (e.g., negative population attitudes and discriminatory laws and policies), interpersonal (e.g., victimization and harassment), and individual level (e.g., internalization of negative societal attitudes and concealment of sexual identity), to drive poor mental health among sexual minorities. Such a socio-ecological system of sexual minority stigma may feature unique characteristics and components, including 1) a chronosystem in which stigma-related factors may vary and exert effects across time, space, and the life course, 2) cross-level effects in which stigma-related factors at one level may give rise to stigma at another level, and 3) mechanisms that explain how stigma-related factors may compromise sexual minorities' mental health.
Purpose and aims:The purpose of this Doctor of Philosophy (Ph.D.) thesis was to contribute to the advancement of sexual minorities' mental health equity by furthering the scientific knowledge on the mechanisms underlying sexual orientation-based disparities in mental health. The Ph.D. thesis aimed to do so by 1) advancing theoretical thinking through combing the existing frameworks of minority stress and psychological mediation with socioecological theory, 2) examining mental health disparities by sexual orientation, and 3) testing different elements of a proposed socio-ecology of sexual minority stigma framework.Methods: Cross-sectional individual-level data were used from surveys sent out to sexual minorities living in Sweden, across Europe, and/or with migration backgrounds. The first two of the presented studies used probability-based sampling techniques to identify representative population-based samples, while the other two studies used convenience samples of sexual minorities who lived in, or have moved from, various countries, diverse in structural climates. Data for the latter two studies were combined with objective indicators of structural forms of stigma present in these countries. In all studies, mediation and/or moderation analyses were employed to examine the explanatory or buffering, respectively, mechanisms underlying the associations between stigma-related factors and sexual minority mental health or wellbeing.