Online school program slowed substance use uptake in Australian teens but had limited effect on cannabis use

The intervention group showed significantly slower increases in binge drinking (OR 0.33), cocaine use (OR 0.06), and prescription drug misuse (OR 0.07) over 12 months compared to controls. Cannabis use showed no significant intervention effect. Drug literacy and harm reduction help-seeking skills remained higher in the intervention group.

Two-arm cluster-randomized controlled trial across 8 secondary schools in New South Wales, Australia. 950 students (mean age 15.9) were assigned to the intervention (5 schools, n=681) or active control (3 schools, n=269). Follow-up at 6 and 12 months.

School-based substance use programs often show weak effects. This online, neuroscience-based approach demonstrated meaningful reductions across multiple substances in a rigorous trial design, though the lack of cannabis-specific effects is notable.

Online harm reduction education may be more effective than traditional approaches for most substances, but cannabis use among teens appears resistant to this type of intervention, suggesting different drivers or cultural factors may be at play.

Unequal cluster sizes (5 vs 3 schools). 37% attrition at 12 months. Self-reported outcomes. Australian context may not generalize to other countries. Active control received standard health education, not no intervention.