Preventing heavy alcohol use in adolescents (PAS): cluster randomized trial of a parent and student intervention offered separately and simultaneously

Abstract

To evaluate the effectiveness of two preventive interventions to reduce heavy drinking in first- and second-year high school students. Cluster randomized controlled trial using four conditions for comparing two active interventions with a control group from 152 classes of 19 high schools in the Netherlands. A total of 3490 first-year high school students (mean 12.68 years, SD=0.51) and their parents. Intervention conditions (i) Parent intervention (modelled on the Swedish Örebro Prevention Program) aimed at encouraging parental rule-setting concerning their children's alcohol consumption; (ii) student intervention consisting of four digital lessons based on the principles of the theory of planned behaviour and social cognitive theory; (iii) interventions 1 and 2 combined; and (iv) the regular curriculum as control condition. Main outcome measures Incidence of (heavy) weekly alcohol use and frequency of monthly drinking at 10 and 22 months after baseline measurement. A total of 2937 students were eligible for analyses in this study. At first follow-up, only the combined student-parent intervention showed substantial and statistically significant effects on heavy weekly drinking, weekly drinking and frequency of drinking. At second follow-up these results were replicated, except for the effects of the combined intervention on heavy weekly drinking. These findings were consistent across intention-to-treat and completers-only analyses. Results suggest that adolescents as well as their parents should be targeted in order to delay the onset of drinking, preferably prior to onset of weekly drinking.