Abstract
Adolescents involved with the juvenile justice system have a high incidence of risky sexual behaviors resulting in unintended pregnancy and sexually transmitted infections. Substance use may be particularly important as a risk factor for unsafe sexual behavior for this group, and recent evidence suggests a possible association between marijuana use and risky sexual behavior. Adolescents (n = 728; 33% female) on probation were followed for 2 years, at intervals of 6 months, to explore the association of marijuana use and condom use longitudinally and at a specific intercourse occasion. Latent growth curve modeling indicated that greater marijuana use at baseline was associated with a steeper decline in condom use over the 2-year period of the study. In-depth analysis of the most recent intercourse occasion suggested that condom use was less likely if marijuana was being used by the participant or his/her partner and that this association was more pronounced if intercourse occurred with someone the participant had just met. Implications for the prevention of risky sexual behavior in this population are discussed.