Delivering prevention for alcohol and cannabis using the Internet: a cluster randomised controlled trial

To establish the efficacy of an internet based prevention program to reduce alcohol and cannabis use in adolescents.

A cluster randomised controlled trial was conducted with 764 13-year olds from ten Australian secondary schools in 2007-2008. Half the schools were randomly allocated to the computerised prevention program (n=397), and half to their usual health classes (n=367). The Climate Schools: Alcohol and Cannabis prevention course is facilitated by the internet and consists of novel, evidence-based, curriculum consistent lessons aimed at reducing alcohol and cannabis use. Participants were assessed at baseline, immediately post, and at six months following the intervention.

Compared to the control group, students in the intervention group showed significant improvements in alcohol and cannabis knowledge at the end of the course and the six month follow-up. In addition, the intervention group showed a reduction in average weekly alcohol consumption and frequency of cannabis use at the six month follow-up. No differences between groups were found on alcohol expectancies, cannabis attitudes, or alcohol and cannabis related harms.

The course is acceptable, scalable and fidelity is assured. It increased knowledge regarding alcohol and cannabis, and decreased use of these drugs.