Age of drinking onset as a moderator of the efficacy of parent-based, brief motivational, and combined intervention approaches to reduce drinking and consequences among college students

Background: The current study tested age of onset as a moderator of intervention efficacy on drinking and consequence outcomes among a high-risk population of college students (i.e., former high school athletes). Methods: Students were randomized to one of four conditions: assessment only control, combined parent-based intervention (PBI) and brief motivational intervention (BMI), PBI alone, and BMI alone. Participants (n = 1,275) completed web-administered measures at baseline (summer before starting college) and 10-month follow-up. Results: Overall, the combined intervention demonstrated the strongest and most consistent reductions across all outcomes, particularly with the youngest initiators. Participants who initiated drinking at the youngest ages had significantly lower peak drinking, typical weekly drinking, and reported consequences at follow-up when they received the combined intervention when compared to the control group. The BMI and PBI groups, when examined independently, demonstrated significant effects across outcomes but were inconsistent across the different age groups. Conclusion: Results suggest the combination of a PBI and a peer-delivered BMI is an appropriate and efficacious way to reduce drinking and related consequences among individuals who initiated drinking earlier in adolescence and are at an increased risk of experiencing alcohol problems.