The GOOD life: Study protocol for a social norms intervention to reduce alcohol and other drug use among Danish adolescents

BACKGROUND It is currently unknown if school-based social norms interventions are effective in preventing harmful alcohol consumption and other drug use among adolescents in Denmark. This paper describes the social norms-based programme The GOOD life and the design of a cluster-randomized controlled trial to test its effectiveness. METHODS/DESIGN The intervention The GOOD life is composed of three social norms components representing three different communication channels, namely face-to-face communication (normative feedback session), print communication (posters) and interactive media (web application). The intervention period of 8 weeks is preceded and followed by data collection, with the follow-up taking place 3 months after baseline. Public schools in the Region of Southern Denmark with grades 8 and 9 are invited to participate in the study and participating schools are randomly allocated to either intervention or control schools. The aim is to recruit a total of 39 schools and a sample of 1.400 pupils for the trial. An online questionnaire is conducted to examine the use of alcohol, tobacco and marijuana as well as the perceived frequency of use among peers of their own grade, which is measured before and after the intervention. Baseline data is used to develop social norms messages which are included in the three intervention components. Primary outcomes are binge drinking (more than 5 units at one occasion) and perceived frequency of binge drinking among peers, while smoking, marijuana use and alcohol-related harm will be assessed as secondary outcomes. DISCUSSION The GOOD life study will provide necessary insights on descriptive and injunctive norms regarding alcohol and other drug use among Danish adolescents. In addition, it will provide new knowledge and insight on the feasibility, implementation context and effectiveness of a newly developed social norms intervention in the Danish school context. TRIAL REGISTRATION Date of registration: 17 February 2016 (retrospectively registered) at Current Controlled Trials with study ID ISRCTN27491960.