Brief motivational and parent interventions for college students: a randomized factorial study.

Using a randomized factorial design, we examined the efficacy of a brief motivational intervention (BMI) and a parent-based intervention (PBI) as universal preventive interventions to reduce alcohol use among incoming college students. Participants (N = 1,014) were assessed prior to matriculation and at 10 months and 22 months postbaseline. Two-part latent growth modeling was used to simultaneously examine initiation and growth in heavy episodic drinking and alcohol-related consequences. This study retained 90.8% (n = 921) of randomized students at the 10-month follow-up and 84.0% (n = 852) of randomized students at the 22-month follow-up. BMI participants were significantly less likely than non-BMI participants to initiate heavy episodic drinking and to begin experiencing alcohol-related consequences. Effect sizes were minimal at 10 months (Cohens h ranged from 0.02 to 0.07) and were small at 22 months (hs ranged from 0.15 to 0.22). A significant BMI x PBI interaction revealed that students receiving both the BMI and the PBI were significantly less likely to report the onset of consequences beyond the sum of the individual intervention effects (h = 0.08 at 10 months, and h = 0.21 at 22 months). Hypothesized direct BMI effects for reductions in heavy episodic drinking and consequences were not observed. Significant mediated effects via changes in descriptive norms were present for both growth and initiation of heavy episodic drinking and consequences. To our knowledge, the current study is the first to provide support for BMI as a universal preventive intervention for incoming college students. Although hypothesized PBI main effects were not found, mediation analyses suggest future refinements could enhance PBI effectiveness.