When less is more and more is less in brief motivational interventions: characteristics of intervention content and their associations with drinking outcomes.

Brief motivational interventions (BMIs) that aim to reduce alcohol use and related problems have been widely implemented in college settings. BMIs share common principles, but vary in specific content. Thus far, the variation in content has not been thoroughly understood in relation to intervention outcomes. The present study addressed this gap by examining variation in breadth of BMI content (i.e., total number of components covered), the extent to which content was personalized to participants, and the interaction between breadth and personalization in relation to treatment outcomes. Data (N = 6,047 participants across 31 separate BMI conditions) came from an integrative data analysis (IDA) study featuring individual-level data from a broad sample of 24 BMI studies of college students. Participants were assessed at baseline and at least 1 follow-up point, conducted up to 12 months postbaseline. Structural equation modeling revealed a significant interaction effect between breadth and personalization of BMI content on alcohol use and related problems at the long-term follow-up (6-12 months) but not at the short-term follow-up (1-3 months). Results indicated that "more is better" for reducing both alcohol use and related problems when BMIs were highly personalized to participants. For less personalized BMIs, coverage of more components was associated with increases in both alcohol use and problems. Findings point to the importance of strategically designing BMIs to maximize their impact on drinking outcomes in college students.