Correlates of cannabis initiation in a longitudinal sample of young women: The importance of peer influences

Objective. Cannabis is the most commonly used illicit drug in developed nations. In adolescent girls especially, rates of cannabis use have increased over the last decade, urging the need to characterize the potential correlates of onset of cannabis use during emerging adulthood. Method. Using data from 1065 females (collected 1994-2005) who participated in both the baseline and follow-up wave of interviews of the Missouri Adolescent Female Twin Study, we examined the associations between correlates from the peer, parental and individual domains and new onsets of cannabis use, using logistic regression. Results. Univariate models revealed that initiation of cannabis use was associated with alcohol and cigarette use at baseline, peer attitude towards alcohol/cigarette/cannabis use, peer substance use and other aspects of impulse-disinhibited behavior. However, multivariate stepwise modeling retained only the significant influences of alcohol use at baseline and peer attitudes towards cannabis as correlates of cannabis initiation. Conclusion. Having peers with favorable attitudes towards alcohol, cigarette and cannabis use is an important correlate of initiation of cannabis use in women. Prevention and intervention efforts need to take this into account when developing drug resistance training programs for adolescents. (C) 2007 Elsevier Inc. All rights reserved.