"Juego de Llaves", a Universal School-based Drug Use Prevention Program: A Non-Randomized Control Cluster Trial for the Evaluation of Effectiveness Among Adolescents in Spain (PISUP)

"Juego de Llaves" is a universal school-based drug prevention program for adolescents aged 12-15 years. The outcome evaluation is critical to determine the quality of preventive interventions. This protocol describes the full protocol of the evaluation design, instruments, randomization procedure, follow-ups, and primary outcomes. Method: Non-Randomized Control Cluster Trial in a set of Spanish school centers at the compulsory secondary education level, with follow-ups at 12-, 24- and 36-months. Participants will be allocated to an experimental or control (no intervention) group. Using an electronic ad-hoc designed App, a battery of instruments will be used to assess addictive behaviors, sociodemographic variables, school climate and other transdiagnostic psychological variables. A piloting test will be conducted to test the implementation protocol and to calculate the sample size needed for the outcome evaluation. After implementing the program, longitudinal statistical approaches will be used to inform on the intervention efficacy and potential moderators and mediators. There is a lack of effectiveness assessments of school prevention programs, and it is expected that this protocol will expedite the monitoring and ongoing evaluation in prevention.