Contingency management is effective in promoting abstinence and retention in treatment among crack cocaine users with a previous history of poor treatment response: a crossover trial

BACKGROUND: Crack use has become a severe health problem in Brazil. Contingency management has shown robust evidence of efficacy in the treatment of cocaine use disorder (CUD) in high-income countries; however, it is still unclear how this intervention can impact treatment in low-income countries. OBJECTIVE: To evaluate the efficacy of contingency management in the treatment of CUD among individuals with a previous history of poor treatment response in Brazil. METHODS: Six months after the end of treatment, 32 participants previously allocated to the usual care condition (UCC) were invited to receive an additional 12 weeks of treatment in a contingency management condition (CMC), and 16 accepted the invitation. We compared data obtained from only the 16 participants (14 male) exposed to both treatment conditions. RESULTS: Participants attended more treatment sessions and were retained in treatment for a longer period during the CMC than during the UCC (p < .01 for both). The proportion of negative cocaine samples submitted, the mean longest duration of cocaine abstinence, and the odds of being abstinent from cocaine during the 12 weeks of treatment were significantly higher during treatment in the CMC when compared to the UCC (p < .05). CONCLUSIONS: This study provides further evidence that contingency management is effective in promoting abstinence and retention in treatment among individuals with CUD with a history of poor treatment response. Our findings argue for the incorporation of CM among public treatment services for CUD in Brazil. TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov as NCT01815645 on March 21, 2013.