Sexual orientation health disparities are well-documented. However, sampling and measurement limitations frequently require researchers to collapse distinct sexual minority subgroups into a single “lesbian, gay, or bisexual” (LGB) analytic group, obscuring subgroup differences in health (e.g., between lesbians/gay men, bisexuals, and heterosexuals reporting same-sex attractions or behaviors [“heterosexual-identified sexual minorities, HSM”]). While a growing, but limited body of research has shown that different subgroups of sexual minorities vary on the basis of mental health status and substance use behaviors, little is known about the factors contributing to subgroup differences in health. This dissertation attempts to fill this gap in the literature using nationally-representative quantitative data. Heterosexuals reporting only opposite-sex attractions and behaviors (“heterosexuals”) are compared to three sexual minority subgroups (lesbians/gay men, bisexuals, and HSM) in each of three studies.

In a first study, group differences in mental health (SF-12) were assessed, and across a range of sociodemographic, lifestyle, and psychosocial characteristics. Next, the degrees to which sociodemographic, lifestyle, and psychosocial characteristics attenuated mental health disparities between heterosexuals and each sexual minority subgroup were assessed. A second study assessed sexual orientation group differences in mental health resilience, among those reporting two or more stressful life events in the past year. Path analysis assessed the degree to which social support mediated (i.e., accounted for) subgroup differences in “thriving” and “languishing” resilience status. In a third study, group differences in DSM-V alcohol, tobacco, and cannabis use disorders were assessed between sexual orientation subgroups. Path analyses assessed the degree to which stressful life events mediated substance use disparities between heterosexuals and sexual minority subgroups, as well as the degrees to which stressful life events and LGB discrimination events mediated differences in substance use among sexual minority subgroups.

Together, findings from all three papers underscore the broad diversity that exists across subgroups of sexual minorities. Further, these papers highlight that while sexual minorities share common experiences of poor mental health and increased substance use, relative to heterosexual people, that important health and social differences also exist within the sexual minority population. These papers contribute new knowledge to our understanding of sexual minority health disparities, and to the social determinants of mental health, resilience, and substance use.