Enhanced Brief Motivational Intervention for College Student Drinkers With ADHD: Goal-Directed Activation as a Mechanism of Change.

College students with attention-deficit/hyperactivity disorder (ADHD) are at risk for alcohol-related problems and disorders relative to their typically developing peers. Despite risk, the optimal therapeutic approach for reducing problem alcohol use in students with ADHD, and mechanisms of change underlying treatment effects in this population, are largely unknown. The current study evaluated putative mechanisms of change in a randomized controlled trial of two harm reduction interventions for college student drinkers with ADHD (N = 113; 49% male): brief motivational intervention plus supportive counseling (BMI + SC) versus brief motivational intervention plus behavioral activation (BMI + BA). Results showed that participants in the BMI + BA condition engaged in more goal-directed activation and less avoidant behavior over the course of treatment compared to those in the BMI + SC condition, in turn predicting reductions in alcohol-related negative consequences. Effects were more robust 1 month following intervention, and diminished by 3 months. Sensitivity analyses revealed a significant indirect effect of treatment condition on alcohol-related negative consequence via reductions in avoidance over treatment. Post hoc moderated mediations showed that BMI + BA engaged target mechanisms more robustly for students with more severe ADHD and depressive symptoms compared to BMI + SC. These findings support the application of BMI + BA intervention, particularly in targeting goal-directed activation and avoidance/rumination in at-risk student drinkers with ADHD.