Changes in peer norms as a mediator of reduction in adolescent alcohol use.

Background: Evidence from college samples suggests that changes in peer norms (perception about peer use) mediate changes in alcohol use. There is relatively little intervention-based research in adolescents. Objectives: To investigate whether changes in peer norms mediate the relationship between a brief intervention to reduce alcohol use, and level of use; additionally, to determine whether any mediation effects differ by adolescent age. Methods: Eighty-four adolescents aged 14-18 (Mean = 16.49, SD = 1.00), presenting to school-based health centers with moderate to high risk alcohol use were randomized to receive an electronic screening and feedback tool (Check Yourself) in addition to their visit, or their visit alone. Check Yourself includes provision of normative feedback regarding adolescent alcohol use. Measures of self-reported alcohol use, and peer norms were collected at baseline and 2-month follow-up. Results: Changes in perceptions of the proportion of peers using alcohol significantly mediated the relationship between the intervention and all three alcohol outcomes (frequency, typical quantity, and maximum quantity) such that reductions in perceived peer use were associated with reduced use. Moderated mediation suggested that these effects were stronger for younger adolescents compared with older adolescents. Perceptions of the frequency and quantity of peer use were not significant mediators of alcohol use. Conclusions/Importance: Results suggest that integrating normative feedback regarding peer alcohol use is a promising approach in adolescent focused school interventions. They extend previous findings by suggesting that perceptions of the proportion of peers using may be particularly meaningful, and that effects may be more pronounced in younger adolescents.