Digital interventions for non-treatment seeking cannabis users in non-clinical settings

Introduction: We conducted a systematic review and meta-analysis to assess the effectiveness of digital-media interventions for cannabis users with a special focus on non-treatment seekers in non-clinical settings.

Method: In November and December 2014, we systematically searched Cochrane Central Register of Controlled Trials Scholar (- 1.1.2015) well as PubMed (1.1.2009 – 1.1.2015), Medline (1.1.2009 – 1.1.2015), Google Scholar (- 1.1.2015) and reference lists of articles. Meta-analyses, systematic reviews, randomized-controlled studies (RCTs) or controlled before and after (CBA) studies testing the effect of an internet, computer, CD-ROM or telephone delivered intervention (with our without additional therapeutic guidance) were included. Effect size (ES) calculations were conducted according to Cohen's d and Hedges. The primary outcome was cannabis use.

Results: 15 studies including n = 12,396 participants and n = 3 systematic reviews or meta-analyses were considered for evaluation. Included trials tested combinations of brief Motivational Enhancement Therapy and Cognitive-Behavioral Therapy. Studies were of excellent to moderate quality (level of evidence: 1 to 3). Eight trials provided relevant data on n = 9 samples of adolescents, who were before or at early stages of cannabis use. Four studies were conducted among adult at-risk cannabis users who were non-treatment seekers or recruited from non-clinical settings. Both overall effect sizes for adolescent prevention studies (overall ES = 0.23) at the 12-month follow-up and for young adult intervention studies (overall ES = 0.25) at the 3-month follow-up assessments were small but significant.

Conclusion: Digital media interventions can help prevent or reduce cannabis consumption among adolescents and adults. Web-, computer or telephone-based programs are promising adjuncts to traditional cannabis prevention and treatment programs.