Mechanisms of Action for Empirically Supported Interventions to Reduce Adolescent Sexual Risk Behavior: A Randomized Controlled Trial

Abstract Purpose Adolescents are at high risk for sexually transmitted infections, including HIV. Interventions to reduce adolescent sexual risk often have modest outcomes. Understanding of the mechanisms of program effectiveness is needed to develop stronger interventions. We used a randomized controlled trial to examine mechanisms of response to two empirically supported interventions: motivational interviewing versus behavioral skills training. Methods A total of 262 adolescents (mean age = 15.89 years, standard deviation = 1.24; 34% female and 61% Latinx) were recruited from juvenile justice programs in the U.S.; all youth were randomized to motivational interviewing or behavioral skills training. Primary outcomes included (1) theory-based mechanisms (condom use attitudes, norms, self-efficacy, and intentions measured before and immediately after the interventions); and (2) risky sexual behavior (frequency of unprotected sex) and condom use measured 3 months postintervention. Results Both interventions significantly increased positive attitudes toward condom use, self-efficacy for condom use, and intentions to use condoms post-test, with no differences by condition. Neither intervention impacted norms for condom use. Both interventions significantly decreased risky sexual behavior and increased condom use at the 3-month follow-up. The pattern of associations of Theory of Planned Behavior constructs to behavior were of similar magnitude in the two groups. Conclusions The results indicate common mechanisms of action for these two interventions and support the use of transdiagnostic mechanisms of treatment impact for sexual risk reduction.