Aims This study aimed to assess the effectiveness of the Örebro prevention programme (ÖPP), an alcohol misuse prevention programme that aims to reduce youth drinking by changing parental behaviour.
Design Cluster-randomized trial, with schools assigned randomly to the ÖPP or no intervention.
Setting Forty municipal schools in 13 counties in Sweden.
Participants A total of 1752 students in the 7th grade and 1314 parents were assessed at baseline. Students' follow-up rates in the 8th and 9th grades were 92.1% and 88.4%, respectively.
Measurements Classroom questionnaires to students and postal questionnaires to parents were administered before randomization and 12 and 30 months post-baseline.
Findings Two-level logistic regression models, under four different methods of addressing the problem of loss to follow-up, revealed a statistically significant programme effect for only one of three drinking outcomes under one loss-to-follow-up method, and that effect was observed only at the 12-month follow-up.
Conclusions The Örebro prevention programme as currently delivered in Sweden does not appear to reduce or delay youth drunkenness.