Skill vs. Disposition: Examining Paths of Intervention Effects in an Alcohol and Drug Use Prevention Trial Targeting U.S. Adolescents.

The goal of this study was to evaluate a mediation model of two approaches to deterring the onset of alcohol, cigarette, and marijuana among middle school adolescents. Students completed surveys that included yes/no self-reports about their past 30-day and lifetime alcohol, cigarettes, and marijuana use. Surveys assessed dispositions: perceptions that drug use would interfere with desired lifestyles, perceptions about drug use prevalence and acceptability, and drug use intentions. Surveys also assessed skills: students' ability to achieve goals, make decisions, and refuse drug use offers. Classrooms were assigned by convenience to one of three conditions. In the control condition, students (N = 394) received no prescribed intervention. Core condition students (N = 101) received instruction in All Stars Core, which targeted changing students' dispositions. Students in the combined Core and Plus condition (N = 135) received instruction in both All Stars Core and in All Stars Plus, which also targeted improving students' skills. Analysis revealed that the programs achieved reductions in the onset of drug use through maintaining these students' dispositions. In contrast, control students' dispositions eroded over time, increasing their risk for drug use. The Plus intervention that targeted skills, failed to have a sufficiently large impact to allow analysis to validate skills as a statistically significant mediator of drug use outcomes. These results speak to the conclusion that, for prevention programs to succeed at deterring the onset of alcohol and drug use, interventions need to maintain or improve students' dispositions. This includes improving lifestyle incongruence, reducing perceptions that drug use is common and acceptable, and by increasing commitments to avoid drugs. Interventions that focus on building skills are less likely to achieve preventive effects.