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

Area of Science:

• Public Health
• Adolescent Psychology
• Intervention Science

Background:

• Denmark faces high rates of hazardous alcohol use among high school students.
• Adolescent alcohol consumption poses significant public health challenges.
• Targeted interventions are needed to mitigate risky drinking behaviors in youth.

Purpose of the Study:

• To evaluate the effectiveness of group motivational interviewing (GMI) and school/parent intervention (SP) in reducing alcohol consumption among Danish high school students.
• To compare the impact of GMI+SP, SP-only, and an assessment-only control group on adolescent drinking patterns.
• To identify effective strategies for preventing hazardous alcohol use in an adolescent population.

Main Methods:

• A 3-arm, cluster-randomized controlled trial involving 2,766 high school students across 16 schools.
• Interventions included 2-session manualized GMI coupled with SP, SP-only, or assessment-only control.
• Data collected via online surveys at baseline and 2, 6, 9, and 12 months, with past-month peak drinks as the primary outcome.

Main Results:

• Students in the control group significantly increased peak drinks per occasion compared to intervention groups.
• Both GMI+SP and SP-only interventions showed significant reductions in peak drinks versus control, though not persistent after p-value correction.
• More substantial effects were observed for the secondary outcome of past-month total drinks consumed.

Conclusions:

• Group motivational interviewing combined with school policies and parental education is a promising strategy for reducing adolescent drinking.
• Developmentally salient relationships (peers, parents) and contexts (school, home) are critical for effective adolescent intervention delivery.
• Findings support the integration of GMI and SP approaches in school-based programs to address hazardous alcohol use in high school students.