Efficacy of a mobile phone-based life-skills training program for substance use prevention among adolescents: study protocol of a cluster-randomised controlled trial

BACKGROUND: Life-skills trainings conducted within the school curriculum are effective in preventing the onset and escalation of substance use among adolescents. However, their dissemination is impeded due to their large resource requirements. Life-skills training provided via mobile phones might represent a more economic and scalable approach. The main objective of the planned study is to test the efficacy of a mobile phone-based life-skills training to prevent substance use among adolescents within a controlled trial. METHODS/DESIGN: The efficacy of a mobile phone-based life-skills training to prevent substance use among adolescents will be tested in comparison to an assessment only control group, within a cluster-randomised controlled trial with two follow-up assessments after 6 and 18 months. The fully automated program is based on social cognitive theory and addresses self-management skills, social skills, and substance use resistance skills. Participants of the intervention group will receive up to 4 weekly text messages over 6 months in order to stimulate (1) positive outcome expectations, e.g., on using self-management skills to cope with stress, (2) self-efficacy, e.g., to resist social pressure, (3) observational learning, e.g. of interpersonal competences, (4) facilitation, e.g., of strategies to cope with negative emotions, and (5) self-regulation, e.g., by self-monitoring of stress and emotions. Active program engagement will be stimulated by interactive features such as quiz questions, message- and picture-contests, and integration of a friendly competition with prizes in which program users collect credits with each interaction. Study participants will be 1312 students between the ages of 14 and 16 years from approximately 100 secondary school classes. Primary outcome criteria will be problem drinking according to the short form of the Alcohol Use Disorders Identification Test and cigarette smoking within the last 30 days preceding the follow-up asses