The effectiveness of a web-based brief alcohol intervention in reducing heavy drinking among adolescents aged 15-20 years with a low educational background: a two-arm parallel group cluster randomized controlled trial

Background: To evaluate the slightly modified version of the web-based brief alcohol intervention "What Do You Drink" (WDYD) among heavy drinking adolescents and young adults aged 15-20 years with a low educational background at one and six months follow-up. Methods: A two-arm parallel group cluster randomized controlled trial was conducted online in the Netherlands in 2011-2012. Participants included in the trial were recruited from preparatory and secondary vocational education institutions and had to be between 15 and 20 years of age and report heavy drinking in the past six months. In total, 73 classes representing 609 (59.9% male) participants were allocated to the experimental condition (37 classes, 318 participants: WDYD intervention) or control condition (36 classes, 291 participants: no intervention). Outcomes were heavy drinking, weekly alcohol consumption, and frequency of binge drinking. Results: Regressions analyses revealed no significant main intervention effects on any of the alcohol outcomes at one and six month's follow-up according to the intention-to-treat principle. Additionally, there were no moderating effects of gender, age, educational level, and readiness to change on the relation between the WDYD intervention and the alcohol outcomes at follow-up. Conclusions: The WDYD intervention was not effective in reducing alcohol consumption among heavy drinking adolescents and young adults aged 15-20 years with a low educational background at one and six months follow-up. However, the absence of intervention effectiveness cannot be used as an argument for not conducting these types of interventions with low educated individuals, since our study was the first to target this population.