The influence of marijuana and alcohol use on condom use behavior: Findings from a sample of young adult female bar drinkers

Prevalence data indicate that alcohol and marijuana are frequently used intoxicants among young adults in the United States. In a number of studies, both alcohol use and marijuana use have been associated with failure to use condoms, a high-risk sexual behavior. The purpose of the current study was to assess the individual and additive effects of alcohol and marijuana use on this risky sexual behavior among 251 young adult, female bar drinkers. Multilevel modeling was used to assess the likelihood of condom use during sexual events that occurred as a function of substance use (none, only alcohol, only marijuana, or both) prior to and partner type (known or casual) during the event, as well as individual differences in sexual assertiveness. Initial model testing (Levels 1 and 2) revealed that there were significant main effects for partner type (known), substance use (alcohol and marijuana) and sexual assertiveness (refusal, pregnancy/STI prevention) on risky sex. Final model testing indicated that sexual assertiveness interacted with substance use to influence risky sex. Women who were low in sexual assertiveness refusal were more likely to engage in risky sex on days when they had consumed both alcohol and marijuana prior to the sexual activity. These findings highlight the complex nature of the relationship between substance use and risky sex.