Personalized Feedback Intervention to Reduce Risky Cannabis Use: Randomized Controlled Trial

This project aims to reduce risky cannabis use among those with less severe cannabis use, most of whom will never seek formal treatment. All of the participants will receive educational material regarding risky cannabis use and its prevention. Half of the participants will also be assigned by chance to receive a personalized feedback report.

The investigators hypothesize that:

1. Participants who receive the full personalized feedback intervention will be less likely to report risky cannabis use at 3- and 6-month follow-ups compared to participants who receive educational materials only (Primary Hypothesis).
2. Participants who receive the full personalized feedback intervention will report greater reductions in their perceptions of how much others use cannabis at a 3-month follow-up compared to participants who receive educational materials only.
3. Reductions in perceptions of how much others use cannabis at 3-month follow-up will be positively associated with reduction in the participant's risky cannabis use at 6-month follow-up.

A 2-arm parallel group randomized controlled trial will be conducted to test these hypotheses with follow-ups occurring at 3 and 6 months after randomization. Online media advertisements will be used to recruit people currently using cannabis. The advertisements will be placed across Canada using locations found successful in previous trials to rapidly recruit participants (e.g. Google AdWords).