The effectiveness of a school-based substance abuse prevention program: 18-Month follow-up of the EU-Dap cluster randomized controlled trial

Abstract Aim To evaluate the effectiveness of a school-based substance abuse prevention program developed in the EU-Dap study (EUropean Drug Addiction Prevention trial). Materials and methods Cluster Randomized Controlled Trial. Seven European countries participated in the study; 170 schools (7079 pupils 12–14 years of age) were randomly assigned to one of three experimental conditions or to a control condition during the school year 2004/2005. The program consisted of a 12-h curriculum based on a comprehensive social influence approach. A pre-test survey assessing past and current substance use was conducted before the implementation of the program, while a post-test survey was carried out about 18 months after the pre-test. The association between program condition and change in substance use at post-test was expressed as adjusted prevalence odds ratio (POR), estimated by multilevel regression models. Results Persisting beneficial program effects were found for episodes of drunkenness (any, POR = 0.80; 0.67–0.97; frequent, POR = 0.62; 0.47–0.81) and for frequent cannabis use in the past 30 days (POR = 0.74; 0.53–1.00), whereas daily cigarette smoking was not affected by the program as it was at the short-term follow-up. Baseline non-smokers that participated in the program progressed in tobacco consumption to a lower extent than those in the control condition, but no difference was detected in the proportion of quitters or reducers among baseline daily smokers. Conclusion The experimental evaluation of an innovative school curriculum based on a comprehensive social influence approach, indicated persistent positive effects over 18 months for alcohol abuse and for cannabis use, but not for cigarette smoking.