Risk moderation of a parent and student preventive alcohol intervention by adolescent and family factors: A cluster randomized trial

Objective: To examine risk moderation of an alcohol intervention targeting parents and adolescents. Design: A cluster randomized trial including 2937 Dutch early adolescents (m=12.68. years, SD=0.51) and their parents randomized over four conditions: parent intervention, student intervention, combined parent-student intervention, and control group. Setting: 152 classes of 19 high schools in The Netherlands (2006). Method: Moderators at baseline (adolescent: gender, educational level and externalizing behavior; parent: educational level and heavy alcohol use) were used to examine the differential effects of the interventions on onset of (heavy) weekly drinking at 22-month follow-up. Results: The combined intervention effectively delayed the onset of weekly drinking in the general population of adolescents, and was particularly effective in delaying the onset of heavy weekly drinking in a higher-risk subsample of adolescents (i.e. those attending lower levels of education and reporting higher levels of externalizing behavior). Conclusion: Present and previous results have established the combined intervention to be universally effective in postponing weekly alcohol use among Dutch adolescents, with an added effect on postponing heavy weekly drinking in high risk subgroups. Therefore, implementation of this intervention in the general population of schools in The Netherlands is advised.Trial registration: NTR649.