Background: Studies of effectiveness of school-based prevention of substance misuse have generally overlooked gender differences. The purpose of this work was to analyse gender differences in the effectiveness of a new European school-based curriculum for prevention of substance misuse among adolescents.
Methods: The EU-Dap trial took place in seven European countries during the school year 2004-05. Schools were randomly assigned to either a control group or a 12-sessions standardized curriculum (“Unplugged”) based on a comprehensive social influence model. The study sample at baseline consisted of 7079 students (3324 boys and 3035 girls). The use of cigarettes, alcohol, and illicit drugs, adolescents’ knowledge and opinions about substances, as well as social and personal skills were investigated through a self-completed anonymous questionnaire administered at enrolment and three months after the end of the program. Adjusted Prevalence Odds Ratios were calculated as measure of association between the intervention and behavioural outcomes using multilevel regression modelling.
Results: At enrolment, boys were more likely than girls to have used cannabis and illicit drugs, while girls had a higher prevalence of cigarette smoking. At post-test, a significant association between program and lower prevalence of all behavioural outcomes was found among boys, but not among girls. Age and self-esteem emerged as possible modifiers of these gender differences, but effects were not statistically significant.
Conclusions: Comprehensive social influence school curricula against substance misuse in adolescence may perform differently among girls and boys, due to developmental and personality factors.