Methods. The Federal Ministry of Education provided a list of 60 federal schools available for the project. Sample size calculations estimated about 4000 pupils were needed for the evaluation study. Considering 45 pupils per class, and 3 classes participating in each school, 32 schools were randomly extracted from the FME list. The extraction was performed at the central level, in OED Institute in Torino, Italy, taking into account the population size of the zones: 6 schools were extracted in NW, 4 in NE, 4 in NC, 2 in FCT, 8 in SW (of which 2 in Lagos), 4 in SE, 4 in SS. A self-completed anonymous questionnaire was created ad hoc for the surveys. To preserve confidentiality, the questionnaires were labelled with a 9-digit individual code self-generated by the student. The questionnaire investigated characteristics of the social environment, tobacco, alcohol and substance use, knowledge, beliefs, and attitudes about substances, the perception of peers and friends use, personal skills, and school climate.
Results. Unplugged was effective in reducing the prevalence of sporadic, regular and daily alcohol use, and of marijuana use among younger pupils, improving negative beliefs on tobacco and alcohol, reducing the erroneous perception of peers’ prevalence of cigarettes, alcohol and marijuana use, with a stronger effect among younger pupils, and improving class climate.
Conclusions. Unplugged reached in Nigeria good results in preventing alcohol and marijuana use, and improving class climate and normative beliefs, similarly to what observed in the European original effectiveness study. Therefore, the implementation of Unplugged at a larger scale in the country can be supported, with the attention of focusing on younger adolescents.