The Acceptance of Contingency Management as a Stand-alone Treatment for Cocaine Use Disorder in Routine Addiction Care: a Naturalistic Cohort Study

INTRODUCTION: Contingency management (CM) is currently recommended for cocaine use disorder by international scientific collaborations and public health institutions. This study addresses the gap between the established efficacy of CM and its implementation in routine clinical practice, by examining the acceptance and course of CM as a stand-alone intervention in patients with cocaine use disorder. METHODS: Twenty-nine cocaine-dependent outpatients participated in a naturalistic cohort study and received a 12-week CM intervention. The primary outcome measures were treatment acceptance and treatment retention. Secondary outcomes included cocaine and other substance use, physical and mental health, quality of life, and impulsivity. RESULTS: Of the 355 patients assessed for eligibility, 57 were offered CM and 29 initiated treatment, resulting in an acceptance rate of 50.9%. Participants attended CM for an average of 6.8 weeks and submitted 42% of scheduled urine samples. Among the 17 participants who submitted at least one cocaine-negative urine sample, eight were classified as having a relatively higher level of abstinence based on the median number of cocaine-negative samples (≥15). In this exploratory subgroup, cocaine use decreased significantly from 13.8 days in the four weeks preceding treatment to 0.6 days in the final four weeks of the intervention, alongside significant reductions in depressive and anxiety symptoms. No serious adverse events occurred. CONCLUSIONS: Despite the small sample size and high dropout rate during CM treatment, this study provides a comprehensive overview of the implementation, progression, and acceptance of CM in a complex patient population. Further research is needed to identify factors influencing treatment acceptance and retention, as well as clinical outcomes and predictors of effective participation in CM.