Digital interventions reduced young adults cannabis use by nearly 7 days per month

Digital interventions reduced cannabis use frequency by 6.79 days in the previous month at 3-month follow-up (95% CI: -9.59 to -4.00, p<.001) compared to controls. 184 behavior change techniques were identified across interventions (range 5-19 per intervention). Feedback on behavior was the most common technique (89% of interventions). Most interventions were web-based.

Systematic review and meta-analysis of 19 RCTs (n=6,710) from 7 databases through February 2023. Included web- or mobile-based interventions for cannabis use in community-dwelling young adults (16-35). Random-effects model with standardized mean differences. Behavior change technique coding applied.

Young adults are the heaviest cannabis users but least likely to seek traditional treatment. Digital interventions can reach this population at scale, and this meta-analysis shows they produce meaningful reductions in use frequency.

The digital intervention field for cannabis is growing rapidly. This meta-analysis establishes that web and mobile approaches can meaningfully reduce use in young adults, though questions remain about optimal dosing, duration, and which specific techniques drive the effect.

High heterogeneity across studies. Mix of passive and active control conditions. Most interventions were web-based, limiting conclusions about mobile apps specifically. 3-month follow-up may not reflect long-term outcomes. Behavior change technique analysis identifies common ingredients but not which are most effective.