Alcohol Use Potentiates Marijuana Problem Severity in Young Adult Women

BackgroundMost young adult women who smoke marijuana also drink alcohol. Marijuana-related problems are associated with marijuana use frequency. We hypothesized that increased alcohol use frequency potentiates the association between frequency of marijuana use and marijuana-related problem severity.MethodsWe recruited women aged 18 to 24 who smoked marijuana at least monthly and were not treatment seeking. Marijuana and alcohol use were measured using the timeline follow-back method. Problems associated with marijuana use were assessed using the Marijuana Problems Scale.FindingsParticipants (n = 332) averaged 20.5 ± 1.8 years of age, were 66.7% non-Hispanic White, and reported using marijuana on 51.5 ± 30.6 and alcohol on 18.9 ± 16.8 of the 90 previous days. Controlling for education, ethnicity, years of marijuana use, and other drug use, frequency of marijuana use (b = .22; p < .01) and frequency of alcohol use (b = 0.13; p < .05) had significant, positive effects on marijuana problem severity. In a separate multivariate model, the linear by linear interaction of marijuana by alcohol use frequency was significant (b = 0.18; p < .01), consistent with the hypothesis.ConclusionsConcurrent alcohol use impacts the experience of negative consequences from marijuana use in a community sample of young women. Discussions of marijuana use in young adults should consider the possible potentiating effects of alcohol use.