Back on track: Feasibility and efficacy randomized trial of a two-week online self-guided intervention for cannabis use reduction

Background and aims: Many individuals aiming to reduce or quit cannabis use prefer self-guided interventions over formal treatment. In this pilot and feasibility randomized trial, we tested a two-week self-guided online intervention combining multiple evidence-based behavior change approaches.
Participants: A total of 168 adults who used cannabis weekly, experienced severe cannabis use disorder on average, and reported being motivated to reduce or quit use participated in the baseline assessment and two-week follow-up of this international online intervention study. An additional three-month follow-up was included. Interventions: Participants were randomized into three conditions: SMART goals alone (minimal intervention control), SMART + mental contrasting with implementation intentions (MCII), or SMART + MCII + Cue-control.
Measurements: Participants set personal reduction or quit goals. We measured subjective goal achievement, objective goal achievement, and cannabis use reduction in grams per week.
Findings: Both intervention conditions outperformed the (minimal intervention) control condition in achieving subjective and objective reduction goals, with 69 % (MCII) and 60 % (MCII + Cue-control) meeting their objective targets compared to 49 % in the control condition. Adding Cue-control to MCII did not enhance outcomes compared to MCII alone. All conditions, including the control, reported similar reductions in cannabis use (grams per week) and these reductions were largely maintained at three-month follow-up. Two-week retention was high in the active intervention groups, especially in the MCII condition, highlighting the accessibility and appeal of the intervention.
Conclusions: This pilot and feasibility randomized trial showed promise of this intervention as an accessible and effective self-guided online cannabis reduction program.