Alcohol use potentiates marijuana problem severity in young adult women

Most 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.

We 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.

Participants (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.

Concurrent 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.