Behavioral therapies for treatment-seeking cannabis users: a meta-analysis of randomized controlled trials

Narrative reviews conclude that behavioral therapies (BTs) produce better outcomes than control conditions for cannabis use disorders (CUDs). However, the strength and consistency of this effect has not been directly empirically examined. The present meta-analysis combined multiple well-controlled studies to help clarify the overall impact of behavioral interventions in the treatment of CUDs. A comprehensive literature search produced 10 randomized controlled trials (RCTs; n = 2,027) that were included in the final analyses. Analyses indicated an effect of BTs (including contingency management, relapse prevention, and motivational interviewing, and combinations of these strategies with cognitive behavioral therapy) over control conditions (including waitlist [WL], psychological placebo, and treatment as usual) across pooled outcomes and time points (Hedges' g = 0.44). These results suggest that the average patient receiving a behavioral intervention fared better than 66% of those in the control conditions. BT also outperformed control conditions when examining primary outcomes alone (frequency and severity of use) and secondary outcomes alone (psychosocial functioning). Effect sizes were not moderated by inclusion of a diagnosis (RCTs including treatment-seeking cannabis users who were not assessed for abuse or dependence vs. RCTs including individuals diagnosed as dependent), dose (number of treatment sessions), treatment format (either group vs. individual treatment or in-person vs. non-in-person treatment), sample size, or publication year. Effect sizes were significantly larger for studies that included a WL control comparison versus those including active control comparisons, such that BT significantly outperformed WL controls but not active control comparisons.