Using marijuana, drinking alcohol or a combination of both: the association of marijuana, alcohol and sexual risk behaviour among adolescents

Background: Although the association between alcohol use and sexual risk behaviour has been well-documented, there is little understanding of whether marijuana use alone or combining marijuana with alcohol use contributes to sexual risk behaviour among adolescents. Methods: A diverse sample of sexually active adolescents (n = 616) aged 12-18 years (50.32% Hispanic; 31.17% Black) completed a survey on alcohol use, marijuana use and sexual risk behaviour during a visit to a primary care clinic. Results: Adolescents were more likely to report having had two or more sexual partners in the past 3 months if they reported using both alcohol and marijuana (OR = 3.90, P < 0.0001), alcohol alone (OR = 2.51, P < 0.0001) or marijuana alone (OR = 1.89, P < 0.001) compared with adolescents who reported no use during the past month. Adolescents were more likely to report having both two or more partners and condomless sex if they used both alcohol and marijuana (OR = 3.19, P < 0.001) or alcohol alone (OR = 3.41, P < 0.01) in the past month compared with adolescents who reported using marijuana alone or had no use of either. Conclusions: Providers should screen for both alcohol and marijuana use among adolescents and discuss how use of alcohol or alcohol in conjunction with marijuana may be associated with sexual risk behaviours.