Assessment of difference in dimensions of sexual orientation: Implications for substance use research in a college-age population

Objective: The present research examines the associations between three distinct dimensions of sexual orientation and substance use in a random sample of undergraduate students. Method: A Web-based survey was administered to students attending a large, midwestern research university in the spring of 2003. The sample consisted of 9,161 undergraduate students: 56% female, 68% white, 13% Asian, 6% black, 4% Hispanic and 9% other racial categories. Using multivariate logistic regression analyses, several measures of alcohol and other drug use were compared across three dimensions of sexual orientation: sexual identity, sexual attraction and sexual behavior. Results: All three dimensions of sexual orientation were associated with substance use, including heavy episodic drinking, cigarette smoking and illicit drug use. Consistent with results of several other recent studies, "nonheterosexual" identity, attraction or behavior was associated with a more pronounced and consistent risk of substance use in women than in men. Conclusions: Study findings suggest substantial variability in substance use across the three dimensions of sexual orientation and reinforce the importance of stratifying by gender and using multiple measures to assess sexual orientation. Study results have implications for future research and for interventions aimed at reducing substance use among college students.