Unplugged, a school-based program that prevents substance use among males but not among females

Background The empirical evidence of effectiveness of school-based programs against substance abuse is rather weak, and most high quality evaluation studies have been conducted in North America. The EU-Dap study is a multicenter cluster randomized trial funded by the European Commission in 2002 and designed to conduct a rigorous evaluation of an innovative school-based curriculum for the prevention of substance use in European junior high schools. Methods The “Unplugged” program, based on a comprehensive social influence approach and consisting of 12 one-hour sessions delivered by class teachers, was implemented in seven European countries during the 2004-2005 school year. One hundred and forty-three schools (7th, 8th and 9th grade) were randomised into three intervention arms (basic curriculum, basic plus peer involvement and basic plus parent involvement), and a usual curriculum control arm. A pre-test survey was conducted before the implementation of the program (n=7079), while two post-test surveys were conducted afterwards, the first 3 months after the end of the program (n=6370), and the second at 1 year follow-up (n=5541). Multilevel Analysis was used to investigate the effectiveness of the program in preventing and reducing drug use at the post test and at one year follow-up. Results At the post-test, the program was effective in reducing the prevalence of use in the last 30 days for all the analysed variables. The Prevalence Odds Ratios of use were 0.70 (0.52-0.94) for daily smoking (>20 cigarettes in the last 30 days), 0.72 (0.58-0.90) for sporadic drunkenness (at least once in the last 30 days), 0.69 (0.48-0.99) for regular drunkenness (>3 times) and 0.77 (0.60-1.00) for sporadic use of cannabis (at least once). At one year follow-up, the effectiveness on cigarettes use was not statistically significant anymore, while the effect on drunkenness episodes was maintained, with a Prevalence Odds Ratio of 0.80 (0.67-0.97) for sporadic drunkenness and of 0.62 (0.47-0.81) for regular drunkenness. The effect on cannabis use was slightly significant, with a POR of 0.74 (0.53-1.01) for regular use (>3 times in the last 30 days). Conclusions The EU-Dap project is the first large European evaluation of a comprehensive drug prevention program for adolescents. At the post test, it reduces of 25-30% the daily use of cigarettes, sporadic and regular drunkenness and sporadic use of cannabis. At one year follow-up, it reduces of 20% sporadic drunkenness episodes and of 40% the regular ones and it is likely to reduce of 25% regular use of cannabis. The program can therefore be recommended as an effective tool to prevent drug use among adolescents.