Effects of a school-based prevention program on European adolescents' pattern of alcohol use.

Purpose: School-based substance abuse prevention programs are widespread but are rarely evaluated in Europe. We aimed to evaluate the effect of a new school-based prevention program against substance use on the frequency of alcohol consumption and alcohol-related problem behaviors among European students. Methods: During the school year 2004–2005, a total of 7,079 students aged 12–14 years from 143 schools in seven European countries participated in this cluster randomized controlled trial. Schools were randomly assigned to either control (65 schools, 3,532 students) or to a 12-session standardized program based on the comprehensive social influence model (78 schools, 3,547 students). Alcohol use and frequency of alcoholrelated problem behaviors were investigated through a self-completed anonymous questionnaire at baseline and 18 months thereafter. The association between intervention and changes in alcohol-related outcomes was expressed as odds ratio (OR), estimated by multilevel regression model. Results: The preventive program was associated with a decreased risk of reporting alcohol-related problems (OR.78, 95% confidence intervals [CI].63–.98), although this reduction was not statistically significant in the subgroup of 743 current drinkers at baseline. The risk for alcohol consumption was not modified by exposure to the program (OR.93, 95% CI.79 –1.09). In the intervention group, nondrinkers and occasional drinkers at baseline progressed toward frequent drinking less often than in the control group. Conclusions: School curricula based on the comprehensive social-influence model can delay progression to frequent drinking and reduce occurrence of alcohol-related behavioral problems in European students. These results, albeit moderate, have potentially useful implications at the population level.