Developmental trajectories of substance use among sexual minority girls: associations with sexual victimization and sexual health risk.

PURPOSE To examine mechanisms underlying the development of sexual health risk behaviors in sexual minority girls (SMGs) and its association with sexual victimization. METHODS Data were drawn from the Project on Human Development in Chicago Neighborhoods cohorts, aged 15 and 18 years (N = 391; 54 SMGs). RESULTS Sexual minority girls reported more sexual victimization and steeper positive trajectories of substance misuse over time than heterosexual girls. Growth in alcohol use during adolescence mediated the link between SMG status and past year number of partners, whereas growth in marijuana use mediated the link between SMG status and self-reported sexually transmitted diseases (STDs). Adding unwanted sexual experiences to the models resulted in a reduction of significance in the direct or indirect effects from SMG status on the sexual health outcomes. Unwanted sexual experiences emerged as a robust predictor directly and indirectly related to past-year number of partners via growth in alcohol use. Unwanted sexual experiences also directly predicted STD history. CONCLUSIONS The increased risk of SMGs for alcohol and marijuana during adolescence, higher rates of sexual partners, and STD diagnosis may also be linked to their significant risk for sexual victimization. Findings highlight the importance of preventive interventions targeting victimization of SMGs.