A cross validation trial of an Internet based prevention program for alcohol and cannabis: Preliminary results from a cluster randomised controlled trial
Objective: Replication is an important step in evaluating evidence based preventive interventions and is crucial for establishing the generalizability and wider impact of a program. Despite this, few replications have occurred in the prevention science field. This study aims to fill this gap by conducting a cross validation trial of the Climate Schools: Alcohol and Cannabis course, an Internet based prevention program, among a new cohort of Australian students. Method: A cluster randomized controlled trial was conducted among 1103 students (Mage: 13.25 years) from 13 schools in Australia in 2012. Six schools received the Climate Schools course and 7 schools were randomized to a control group (health education as usual) All students completed a self report survey at baseline and immediately post intervention. Mixed effects regressions were conducted for all outcome variables. Outcomes assessed included alcohol and cannabis use, knowledge and intentions to use these substances. Results: Compared to the control group, immediately post intervention the intervention group reported significantly greater alcohol (d 0.67) and cannabis knowledge (d 0.72) were less likely to have consumed any alcohol (even a sip or taste) in the past 6 months (odds ratio 0.69) and were less likely to intend on using alcohol in the future (odds ratio 0.62) However, there were no effects for binge drinking, cannabis use or intentions to use cannabis. Conclusion: These preliminary results provide some support for the Internet based Climate Schools: Alcohol and Cannabis course as a feasible way of delivering alcohol and cannabis prevention. Intervention effects for alcohol and cannabis knowledge were consistent with results from the original trial; however, analyses of longer term follow up data are needed to provide a clearer indication of the efficacy of the intervention, particularly in relation to behavioral changes.
The Australian and New Zealand journal of psychiatry