This trial examines the effectiveness of a novel neurodevelopmentally informed intervention - Adolescent Developmentally-Appropriate health Promotion Therapy (ADAPT) - on preventing alcohol use and promoting well-being among students in middle school in a heavy adolescent alcohol use region (Denmark). Using a 2-condition cluster-randomized controlled trial of students in 8th grade (ages 13-15), the following hypotheses are tested:

1. Compared to adolescents in the Delayed Treatment Condition (DTC), ADAPT adolescents will show significant reductions in intentions to drink (primary outcome) from baseline to 3 months post intervention.
2. Compared to adolescents in the DTC, ADAPT adolescents will show significant reductions in alcohol use and alcohol-related consequences, and significant increases in well-being and life satisfaction (secondary outcomes) from baseline to 3 months.

Additionally, acceptability and feasibility is examined.

The main aim of this trial is to examine the effectiveness of a novel neurodevelopmentally informed intervention - Adolescent Developmentally-Appropriate health Promotion Therapy (ADAPT) - on preventing alcohol use and promoting well-being among students in middle school in a heavy adolescent alcohol use region (Denmark). Furthermore, we aim to examine ADAPT's feasibility and acceptability with students in middle school, their parents, and with staff (e.g., teachers and principals), to inform and guide next step, larger scale randomized controlled trials.

The study employs a 2-condition cluster-randomized controlled design in 8th grade students (ages 13-15), with the following conditions:

1. ADAPT: ADAPT intervention (consisting of three group sessions with students and one meeting with parents per school class) will be conducted by study staff immediately after baseline.
2. Delayed Treatment: ADAPT is offered to interested schools after the 3-month follow-up survey is completed.

The following hypotheses are tested:

1. Compared to adolescents in the DTC, ADAPT adolescents will show significant reductions in intentions to drink (primary outcome) from baseline to 3 months post intervention.
2. Compared to adolescents in the DTC, ADAPT adolescents will show significant reductions in alcohol use and alcohol-related consequences, and significant increases in well-being and life satisfaction (secondary outcomes) from baseline to 3 months.

All participants will complete an online baseline survey pre-intervention and online follow-ups at 1- and 3-months. Due to the large target N (N=1000), we will randomize students (and schools) in two blocks. The primary and secondary outcomes will be analyzed using generalized estimation equations (GEE) to account for the nested data structure: repeated measures, nested within students, nested within groups, nested within school classes, nested within schools. Feasibility of ADAPT will be measured quantitatively via student enrollment and attendance in ADAPT groups sessions, and parent attendance in the parent meeting. Acceptability of ADAPT will be measured via surveys (students, parents) and interviews (school staff).

Inclusion Criteria:

• Students starting 8th grade in August 2025 in one of the participating public middle schools
• Understand and speak Danish
• Able to give informed active consent with informed passive consent from parents/guardians

Exclusion Criteria:

- Not fulfilling inclusion criteria

After the conclusion of the study, data from the study will be made available by the Centre for Alcohol and Drug Research, Aarhus University, upon reasonable request, and within the limitations set by the Danish data protection legislation and regulation.