A randomized, controlled trial of combined cognitive-behavioral therapy plus prize-based contingency management for cocaine dependence

Background Cocaine has become one of the drugs of most concern in Switzerland, being associated with a wide range of medical, psychiatric and social problems. Available treatment options for cocaine dependence are rare. The study sought to compare combined prize-based contingency management (prizeCM) plus cognitive-behavioral therapy (CBT) to CBT alone in cocaine-dependent patients. Methods Sixty cocaine-dependent patients participated in a randomized, controlled trial with two treatment conditions. The participants were randomly assigned to the experimental group (EG; n = 29), who received CBT combined with prizeCM, or to the control group (CG; n = 31), who received CBT only during 24 weeks. The primary outcome measures were retention, at least 3 consecutive weeks of cocaine abstinence, the maximum number of consecutive weeks of abstinence and proportions of cocaine-free urine samples during the entire 24-week and at 6-month follow-up. Results Sixty-three percent of the participants completed the study protocol. Participants in both groups significantly reduced cocaine use over time. Overall, no difference in cocaine-free urine screens was found across the two treatment groups, except at weeks 8, 9, 10, 17 and 21 in favor of the EG. Conclusions The addition of prizeCM to CBT seems to enhance treatment effects, especially in the early treatment period, supporting results from previous studies. Both the combined intervention and CBT alone, led to significant reductions in cocaine use during treatment and these effects were sustained at 6-month follow-up. These findings underline the importance in implementing CM and CBT interventions as treatment options for cocaine dependence in the European context.