Improving substance misuse outcomes in Contingency Management treatment with adjunctive formal psychotherapy: A systematic review and meta-analysis dataset

Introduction Contingency Management is a treatment for substance misuse that involves rewarding behaviour change using financial incentives. While there is a solid body of evidence demonstrating its efficacy during treatment, concerns have been raised that it does not improve intrinsic motivation or provide coping strategies to maintain change. It has been suggested that there may be a synergistic relationship between Contingency Management and other formal structured psychotherapies, such as Cognitive Behavioural Therapy (CBT) or Motivational Enhancement Therapy (MET). Objectives The aim of this review is to examine whether adding another formal psychotherapy to Contingency Management improves substance use outcomes at either treatment end or at post-treatment follow-up. Methods A search was performed of seven electronic bibliographic databases as well as of online trial registries, followed by reference list screening. Design Included studies were randomised controlled trials of adults (18-65). Setting Any setting was included Participants Participants were using illicit substances, alcohol, or tobacco use; Interventions: Included studies featured an experimental arm delivering contingency management combined with a structured evidence-based psychotherapeutic intervention and a Contingency Management only arm Primary and Secondary Outcomes: Biometrically verified or self-reported measure of substance use at treatment end. The primary outcome was biometrically verified point prevalent abstinence (PPA) at treatment end. Secondary outcomes included biometrically verified PPA at post-treatment follow-up and self-reported days of use at treatment end and post-treatment follow-up. Results 12 studies (n=1,654) were included. Nine targeted illicit substance use, two tobacco, and one polysubstance use. Seven studies included CBT and/or MET, while the other five featured other structured psychotherapeutic packages. The primary analysis found no evidence of a synergistic effect in PPA at treatment end (Relative Risk (RR) 0.97, 95% CI 0.85, 1.09; p=0.58). Sensitivity analysis of the CBT/MET studies only also found no evidence of an effect. Secondary outcomes included PPA at post-treatment follow-up and self-reported substance use at both time points. None of the secondary outcomes showed any evidence of benefit. Conclusion The results of the meta-analyses found no evidence that combining CM with another intervention improves the short-term or long-term effects of CM treatment. The conclusions of this review suggest psychotherapeutic interventions (including cognitive-behavioural) do not enhance CM treatment. Instead, alternative approaches may be required to improve outcomes of treatment