Method: The authors used data from the second California Quality of Life Survey (Cal-QOL II), a followback telephone survey in 2008-2009 of individuals first interviewed in the population-based 2007 California Health Interview Survey. The sample comprised 2,671 individuals, oversampled for minority sexual orientation. Respondents were administered a structured interview assessing past-year alcohol and illicit drug use, perceptions of perceived illicit drug availability, and injunctive norms concerning illicit drug and heavier alcohol use. The authors used structural equation modeling methods to test a mediational model linking sexual orientation and substance use behaviors via perceptions of drug availability and social norms pertaining to substance use.

 

Results: Compared with heterosexual individuals, sexual minorities reported higher levels of substance use, perceived drug availability, and tolerant social norms. A successfully fitting model suggests that much of the association between minority sexual orientation and substance use is mediated by these sexual orientation-related differences in drug availability perceptions and tolerant norms for substance use.

Conclusions: Social environmental context, including subcultural norms and perceived drug availability, is an important factor influencing substance use among sexual minorities and should be addressed in community interventions.​