Digital Interventions for Problematic Cannabis Users in Non-Clinical Settings: Findings from a Systematic Review and Meta-Analysis

Background: Existing cannabis treatment programs reach only a very limited proportion of people with cannabis-related problems. The aim of this systematic review and meta-analysis was to assess the effectiveness of digital interventions applied outside the health care system in reducing problematic cannabis use. Methods: We systematically searched the Cochrane Central Register of Controlled Trials (2015), PubMed (2009-2015), Medline (2009-2015), Google Scholar (2015) and article reference lists for potentially eligible studies. Randomized controlled trials examining the effects of internet-or computer-based interventions were assessed. Study effects were estimated by calculating effect sizes (ESs) using Cohen's d and Hedges' g bias-corrected ES. The primary outcome assessed was self-reported cannabis use, measured by a questionnaire. Results: Fifty-two studies were identified. Four studies (including 1,928 participants) met inclusion criteria. They combined brief motivational interventions and cognitive behavioral therapy delivered on-line. All studies were of good quality. The pooled mean difference (Delta = 4.07) and overall ES (0.11) give evidence of small effects at 3-month follow-up in favor of digital interventions. Conclusions: Digital interventions can help to successfully reduce problematic cannabis use outside clinical settings. They have some potential to overcome treatment barriers and increase accessibility for at-risk cannabis users. (C) 2016 S. Karger AG, Basel