Does it really matter which drug you choose? An examination of the influence of type of drug on type of risky sexual behavior.

This study investigates whether certain types of substances are differentially related to certain risky sexual behaviors (RSBs) within the same population and determines whether combination substance use (SU) has additive, redundant or antagonistic effects on RSBs. African-American youth aged 9-19 participated in a large, community-based survey assessing substance use and sexual behaviors. Multilevel modeling was used to predict the differential influence of alcohol, marijuana, and cocaine use on condom use measured in the past 90days and at last intercourse, sex while drunk/high, and number of sexual partners. Tests of the within-participant relations showed that participants increasing their SU over time concurrently increased their RSBs, establishing a strong link between the two behaviors (alcohol: condom β=-0.045, sex while drunk/high β=0.138, sex partners β=0.102; marijuana: condom β=-0.081, sex while drunk/high β=0.255, sex partners β=0.166; cocaine: condom β=-0.091, sex while drunk/high β=0.103, sex partners β=0.031; all p's<0.01). Tests of the between-participant relations showed that, generally, youth reporting less SU across their teenage years were also more likely to report fewer RSBs over this period (alcohol: condom β=-0.128, sex while drunk/high β=0.120, sex partners β=0.169; marijuana: condom β=-0.170, sex while drunk/high β=0.638, sex partners β=0.357; cocaine: condom β=-0.353; all p's<0.05). Moreover, the combination of some substances has unique redundant or antagonistic effects on RSB. Such findings support the consideration of type of SU, and particular combinations of substances, on RSBs in intervention development.