Background: Frequent cannabis use has been associated to a variety of negative mental, physical and, social consequences. We assessed the effects of digital prevention and treatment interventions regarding the reduction in cannabis use compared to control conditions.
Methods: Systematic review with two separate meta-analyses. Thirty randomized controlled trials met the inclusion criteria for the systematic review and 21 were included in the meta-analyses. The primary outcome was cannabis use through self-report at post-treatment and follow-up assessments. Hedges’ g was calculated for all comparisons with non-active controls. The risk of bias was examined according to the Cochrane Risk of bias tool.
Results: The systematic review included 10 prevention interventions targeting 8138 participants (aged between 12 and 20) and 20 treatment interventions targeting 5195 cannabis users (aged between 16 to 40). The meta-analyses showed that digital interventions significantly reduced cannabis use in the prevention interventions compared with control conditions (six studies, n=2564, g=0.33; 95% CI=0.13-0.54, P=0.001) and in the treatment interventions compared with control conditions (17 comparisons, n=3813, g=0.12; 95% CI=0.02-0.22, P=0.02) at post-treatment. The effects were maintained up to 12 months during the follow-up assessments for prevention interventions (five comparisons, n=2445, g=0.22; 95% CI=0.12-0.33, P < 0.001) but did not reach statistical significance for the treatment interventions.
Conclusions: Digital prevention and treatment interventions displayed small and significant cannabis use reduction effects among diverse target populations at post-treatment compared to control conditions. The post-treatment effects of prevention interventions were maintained up to 12 months during the follow-up assessments