Three-Arm Randomized Controlled Trial of Motivational Interviewing for Adolescent Drinking in Denmark

To test the effectiveness of group motivational interviewing (GMI) and school/parent intervention (SP) in reducing drinking among public high school students in Denmark, a region with high rates of hazardous alcohol use.

This was a 3-arm, cluster-randomized controlled trial in 16 public high schools block-randomized to the following: (1) 2-session, manualized GMI coupled with SP; (2) SP-only; or (3) assessment-only control. A total of 2,766 students (65.53% female; mean age = 16.77 years, range = 15-19 years) completed online surveys during class periods at baseline and at 2, 6, 9, and 12 months. The primary outcome was past-month peak drinks per occasion at 12-month follow-up. Mixed models estimated change from baseline for each condition and mean change difference across conditions.

Students in the control condition significantly increased peak drinks over time at 2.5 times the rate of the other conditions (Δmean = 1.13 [95% CI = 0.62, 1.64] vs 0.48 [95% CI = 0.03, 0.93] for GMI+SP and 0.47 [95% CI = 0.06, 0.88] for SP-only). The mean change difference in peak drinks for each GMI+SP and SP-only vs control was significant (Δmean = -0.65 [95% CI = -1.28, -0.02] and -0.66 [95% CI = -1.27, -0.04], respectively), although significance did not persist after p value correction. More robust effects were observed for the secondary outcome of past-month total drinks.

GMI coupled with school-based alcohol policies and parental education represents a promising approach to mitigating drinking among high school students. This study supports the crucial roles of developmentally salient relationships (eg, peers, parents/guardians) and contexts (eg, school, home) in developing and delivering intervention programs to adolescents.

Prevention of Hazardous Use of Alcohol with Danish High School Students (Our Choice); https://clinicaltrials.gov/study/NCT06018389?cond=NCT06018389.