Background The empirical evidence of effectiveness of school-based programs against substance abuse is rather weak. A recent Cochrane review pointed out that most high quality evaluation studies in this field have been conducted in North America, where only skills-based programs seemed to be effective in preventing drug use. The EU-Dap project was funded in 2002 by the European Commission in order to assess the effectiveness of a novel program based on a Comprehensive Social Influence approach. This paper summarises the results from the multicenter cluster randomized trial designed to evaluate the behavioural changes associated to the curriculum, and presents a preliminary identification of potential mediators of these changes. Methods The “Unplugged” program consisted of 12 one-hour sessions delivered by class teachers to 12-14 year old students in seven European countries during the school year 2004-2005. Schools (n=170) were randomised to three intervention arms (basic curriculum alone or involving activities with class peers or parents) and a usual curriculum control arm. A pre-test survey was conducted before the implementation of the program (n=7079), while two follow-up surveys conducted 3 and 15 months after the intervention involved 6370 and 5541 students, respectively. Multilevel Analysis was used evaluate the effect of the program on the prevalence of substance use. Factorial analysis was conducted in order to identify the potential mediators of the program’s effects. Cronbach α, mean, standard deviation, and minimum and maximum scores were calculated. Results At the 15-month follow-up, there was no program effect on cigarettes use while the effect on drunkenness observed at the short-term follow-up 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. A POR of 0.74 (0.53-1.01) for regular cannabis use (>3 times in the last 30 days) was also found. In order to perform a mediation analysis, 32 variables were identified, loading on 7 main areas of intermediates (Intentions, Social norms, Attitudes and beliefs, Knowledge, Social Support, School experience, Personal skills). The values of Cronbach were of acceptable size. Conclusions The EU-Dap study is the first large European evaluation of a universal drug prevention program for adolescents. At the 15-month post test, it was associated to a 25-30% reduction of sporadic and regular drunkenness and sporadic use of cannabis. In order to carry out a mediation analysis, 32 variables loading on seven factors were identified.
Effects and mediators of effects of an European school-based program for drug use prevention: preliminary results from the EU-Dap cluster randomized trial
VIGNA-TAGLIANTI, Federica;
2009-01-01
Abstract
Background The empirical evidence of effectiveness of school-based programs against substance abuse is rather weak. A recent Cochrane review pointed out that most high quality evaluation studies in this field have been conducted in North America, where only skills-based programs seemed to be effective in preventing drug use. The EU-Dap project was funded in 2002 by the European Commission in order to assess the effectiveness of a novel program based on a Comprehensive Social Influence approach. This paper summarises the results from the multicenter cluster randomized trial designed to evaluate the behavioural changes associated to the curriculum, and presents a preliminary identification of potential mediators of these changes. Methods The “Unplugged” program consisted of 12 one-hour sessions delivered by class teachers to 12-14 year old students in seven European countries during the school year 2004-2005. Schools (n=170) were randomised to three intervention arms (basic curriculum alone or involving activities with class peers or parents) and a usual curriculum control arm. A pre-test survey was conducted before the implementation of the program (n=7079), while two follow-up surveys conducted 3 and 15 months after the intervention involved 6370 and 5541 students, respectively. Multilevel Analysis was used evaluate the effect of the program on the prevalence of substance use. Factorial analysis was conducted in order to identify the potential mediators of the program’s effects. Cronbach α, mean, standard deviation, and minimum and maximum scores were calculated. Results At the 15-month follow-up, there was no program effect on cigarettes use while the effect on drunkenness observed at the short-term follow-up 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. A POR of 0.74 (0.53-1.01) for regular cannabis use (>3 times in the last 30 days) was also found. In order to perform a mediation analysis, 32 variables were identified, loading on 7 main areas of intermediates (Intentions, Social norms, Attitudes and beliefs, Knowledge, Social Support, School experience, Personal skills). The values of Cronbach were of acceptable size. Conclusions The EU-Dap study is the first large European evaluation of a universal drug prevention program for adolescents. At the 15-month post test, it was associated to a 25-30% reduction of sporadic and regular drunkenness and sporadic use of cannabis. In order to carry out a mediation analysis, 32 variables loading on seven factors were identified.
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