Young Sexual Minority Women's Mental Health: Developmental Trajectories, Mechanisms of Risk, and Protective Factors. - Sexual minority women experience alarmingly high rates of mental health problems, including anxiety disorders, depression, and suicidality, which are significantly higher than those of both heterosexual women and sexual minority men. The overarching goals of this project are to address these mental health disparities and advance our ability to prevent and treat mental illness among sexual minority women by conducting an innovative, longitudinal study of mental health in young sexual minority women. Building upon the largest ever longitudinal cohort study of young sexual minority women, which includes seven waves of data collected over 3 years from 390 racially diverse participants (ages 16-20 at baseline), we will collect an additional six waves of data over 2.5 years (starting at ages 21-26) with expanded measurement of mental health, risk and protective factors, and mechanisms of effect. We have four specific aims: (1) Model trajectories of sexual minority women’s mental health, including depression, anxiety, and suicidality across late adolescence and early adulthood (16-28 years), and explore demographic differences in these patterns (e.g., by race, gender identity). (2) Grounded in minority stress theory, rigorously test unique stigma-based risk factors for mental health among sexual minority women. (3) Explore biological, psychological, and social/interpersonal mechanisms through which minority stress negatively affects sexual minority women’s mental health. Specifically, we will test whether stress-sensitive inflammatory processes (C- reactive protein, IL-6, IL-10, TNFa), maladaptive emotion regulation and cognitive processes (e.g., rumination; hopelessness), and impaired social processes (social isolation; romantic relationship functioning) mediate associations between minority stress and mental health. (4) Identify individual, community, and interpersonal protective factors that buffer sexual minority women from adverse mental health effects of minority stress. Across aims, the project focuses on identifying mutable factors that can be targeted in interventions and are relevant to today’s young sexual minority women, who are diverse in race, gender identity, and specific sexual orientation identity. Findings will be used to inform development of evidence-based, culturally sensitive interventions to prevent and treat mental illness in this vulnerable group. This proposal is responsive to NOT-MD-19-001(Notice of Special Interest in Research on the Health of SGM Populations), which encourages research describing biological and social processes affecting the health of sexual and gender minorities (SGM) that will lead to the development of interventions to enhance SGM health.