["Klar bleiben" (keep a clear head)-a competition for school classes to reduce alcohol consumption].

In Germany, alcohol is the most popular drug among adolescents. So far, school-based alcohol prevention programs have focused on elementary school children and pupils in early adolescence. The school program "Klar bleiben" ("Keep a Clear Head") was especially designed for young people in late adolescence (10th graders) with the aim of establishing non-binge drinking as a social norm.Students in the participating classes commit themselves to abstain from binge drinking for six weeks (contract management). The class gives feedback after each week. After at least five positive feedbacks, the class is rated as successful and enters a prize draw. Elaborated teaching impulses and information resources for teachers and parents are further components of the prevention program.The evaluation of the class competition by 92 teachers can be regarded as consistently positive. The results of a cluster-randomized study showed a relative risk reduction of 10.4% in binge drinking in the last month for those adolescents who had already consumed alcohol before and belong to the intervention group. After the end of the intervention, this group of adolescents consumed an average of 0.19 fewer alcoholic beverages per drinking occasion compared to adolescents from the control group. The findings presented here are encouraging, keeping in mind that the intervention is relatively inexpensive.