Sexual orientation and drug use in a longitudinal cohort study of U.S. adolescents.

Adolescents with a minority sexual orientation (e.g., lesbian, gay, and bisexual) are more likely to use substances than their heterosexual peers. This study aimed to increase understanding of the development of drug use in this vulnerable population by: 1) comparing longitudinal patterns of past-year illicit drug use (e.g., marijuana, cocaine, and ecstasy) and misuse of prescription drugs among minority sexual orientation youth relative to heterosexual youth and, 2) examining how sexual orientation sub-group, gender, and age relate to variation in the risk of drug use. Data come from the Growing Up Today Study, a community-based cohort of U.S. adolescents who were assessed three times between 1999 and 2005 with self-administered questionnaires when they ranged in age from 12 to 23 years (N=12,644; 74.9% of the original cohort). Multivariable repeated measures generalized estimating equations using modified Poisson regression were used to estimate relative risks. Participants indicating their sexual orientation was mostly heterosexual, bisexual, or lesbian/gay were more likely than completely heterosexual youth to report past-year illicit drug use and misuse of prescription drugs. Gender was an important modifier; bisexual females were most likely to report drug use. Age was also an important modifier of risk; differences in drug use between minority sexual orientation and heterosexual youth were larger during adolescence (12-17 years) than during emerging adulthood (18-23 years). Research must focus on identifying reasons why minority sexual orientation youth are at disproportionate risk for drug use. Such information is essential for developing interventions that are critically needed to reduce drug use in this population. Efforts need to begin early because large sexual orientation disparities in drug use are evident by adolescence.