Aims
To evaluate the effectiveness of two preventive interventions to reduce heavy drinking in first- and second-year
highschoolstudents.
Designandsetting
Clusterrandomizedcontrolledtrialusingfourconditionsforcomparingtwo
activeinterventionswithacontrolgroupfrom152classesof 19highschoolsintheNetherlands.
Participants
Atotal
of 3490 first-year high school students (mean 12.68 years, SD
=
0.51) and their parents.
Intervention conditions
(i)
Parentintervention(modelledontheSwedishÖrebroPreventionProgram)aimedatencouragingparentalrule-setting
concerning their children’s alcohol consumption; (ii) student intervention consisting of four digital lessons based on
theprinciplesof thetheoryof plannedbehaviourandsocialcognitivetheory;(iii)interventions1and2combined;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.
Findings
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.
Conclusions
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