Date of Conferral



Doctor of Public Health (DrPH)


Public Health


Vasileios Margaritis


Sexual minorities (lesbians, gays, and bisexuals) have a greater risk for substance abuse and mental illness than sexual majorities (heterosexuals). Associations between substance abuse and mental illness among sexual minority adults have not been widely studied. The purpose of this quantitative cross-sectional study was to use the 2015 National Survey on Drug Use and Health data from the Substance Abuse and Mental Health Administration to study the association of substance abuse (alcohol; hard drugs such as heroin, cocaine, methamphetamine; and hallucinogens), prescribed drugs (pain relievers, tranquilizers, sedatives, stimulants, psychotherapeutic, and inhalants, as well as marijuana) and mental illness (no past year, mild, moderate, and severe in the past year) among sexual minority adults ages 18 and older in the United States. Confounding factors that may influence these associations were controlled. The theoretical framework for this study was Meyer's minority stress model. The sample was 43,561 adults. Chi-square and logistic regression analyses were performed to estimate odds for mental illness by drug type. Findings showed that higher odds of mental illness were significantly associated with prescribed drugs and marijuana abuse (OR: 3.48, 95% CI:1.66, 7.29) among gays/lesbians, and with alcohol abuse among bisexuals (OR: 2.31, 95% CI: 1.62, 3.29). Positive social change resulting from this study may include increased knowledge of associations between substance abuse and mental illness among sexual minority adults and guidance for public health interventions to improve sexual minorities' access to early substance abuse and mental health prevention and treatment.