Open access Original research BMJ Open: first published as 10.1136/bmjopen-2019-034735 on 8 October 2020. Downloaded from Improving substance misuse outcomes in contingency management treatment with adjunctive formal psychotherapy: a systematic review and meta- analysis Luke Sheridan Rains ,1 Thomas Steare,1 Oliver Mason,2 Sonia Johnson 1 To cite: Sheridan Rains L, ABSTRACT Strengths and limitations of this study Steare T, Mason O, et al. Objectives Contingency management (CM) is a treatment Improving substance for substance misuse that involves the provision of ► This is the first systematic review to focus on the misuse outcomes in incentives. This review examines the hypothesis that contingency management benefits of combining contingency management adding another formal psychotherapy, such as cognitive– treatment with adjunctive with another psychotherapy as a potential method behavioural therapy (CBT) or motivational enhancement formal psychotherapy: a for improving treatment. therapy (MET), to CM improves substance use outcomes systematic review and ► Use of the Grading of Recommendations Assessment, at both treatment end and at post- treatment follow- up meta- analysis. BMJ Open Development and Evaluation approach to identify compared with CM only. 2020;10:e034735. doi:10.1136/ moderate overall quality of evidence across 10 ran- bmjopen-2019-034735 Data sources Searches were performed in December domised controlled trials. 2017 and July 2019 of seven electronic bibliographic ► Prepublication history for ► Lack of sufficient detail in reviewed trials to assess databases (MEDLINE, PsycINFO, EMBASE, Scopus, Web this paper is available online. bias across all dimensions. of Science, CINAHL, PsycEXTRA), as well as online trial To view these files, please visit ► Significant heterogeneity among the psychotherapy the journal online (http:// dx. doi. registries and EThoS, and were followed by reference list interventions for which content was often unclear. copyright. org/ 10. 1136/ bmjopen- 2019- screening. ► Inability to perform subgroup analysis by cognitive– 034735). Eligibility criteria Included studies were randomised behavioural therapy treatment design or other study controlled trials of adults (18–65) who were using differences such as substance or cohort. Received 31 October 2019 illicit substances, alcohol or tobacco. Studies featured Revised 25 June 2020 an experimental arm delivering CM combined with a Accepted 04 August 2020 http://bmjopen.bmj.com/ structured evidence- based psychotherapeutic intervention and a CM- only arm. Studies published up to July 2019 adherence to treatment is reinforced using were included. rewards (or less often punishments). In most Data extraction and synthesis The primary outcome cases, these are financial incentives such as a was biometrically verified point prevalent abstinence (PPA) at treatment end. Secondary outcomes included voucher or cash. Since its development in the biometrically verified PPA at post- treatment follow- up 1960s, a significant evidence base has been and self- reported days of use at treatment end and post- amassed demonstrating the effectiveness of CM across a variety of cohorts and behaviours.1–3 treatment follow- up. Pooled risk ratios for PPA outcomes on October 12, 2020 at UCL Library Services. Protected by and standardised mean differences for days of use were There is now good evidence of the effective- calculated using random effects models. Risk of bias ness of CM for smoking cessation,4 alcohol5 was assessed using the Grading of Recommendations and substance misuse.1 Moreover, while there is Assessment, Development and Evaluation. solid and growing evidence base for a range of Results 12 studies (n=1654) were included. The primary formal psychotherapies in substance use disor- analysis found no evidence of a synergistic effect in PPA at ders, including cognitive–behavioural therapy © Author(s) (or their treatment end (relative risk (RR) 0.97, 95% CI 0.85 to 1.09; (CBT), motivational interviewing/motiva- employer(s)) 2020. Re- use p=0.57). Sensitivity analysis of studies featuring CBT/MET permitted under CC BY- NC. No tional enhancement therapy (MI/MET), also found no evidence of an effect (RR 0.92; 95% CI 0.79 3 6–8 commercial re- use. See rights mindfulness- based meditation, CM is typi- and permissions. Published by to 1.08; p=0.32). None of the secondary outcomes showed BMJ. any evidence of benefit. cally found to confer the greatest benefit. In a systematic review over a decade ago, Dutra et al3 1Division of Psychiatry, Conclusion The results of the meta- analyses found no University College London, evidence that combining CM with another intervention found that CM was more effective at reducing London, UK improves the short- term or long- term effects of CM use than CBT or relapse prevention treat- 2School of Psychology, University treatment. ments, but CM in combination with CBT was of Surrey, Guildford, UK more effective than either CM or CBT alone. Correspondence to INTRODUCTION In the UK, the National Institute for Health 9 Dr Luke Sheridan Rains; Contingency management (CM) is a treatment and Care Excellence (NICE) recommends l. sheridanrains@ ucl. ac. uk for substance misuse in which abstinence or that drug services introduce CM programmes. Sheridan Rains L, et al. BMJ Open 2020;10:e034735. doi:10.1136/bmjopen-2019-034735 1 Open access BMJ Open: first published as 10.1136/bmjopen-2019-034735 on 8 October 2020. Downloaded from Although CM has a strong evidence base, some have and/or lack the skills to maintain abstinence’.12 These argued that any effects are likely to be short-lived as the aims, if successful, could aid participants with main- motivational benefit of rewards will end when the rewards taining abstinence post- treatment. A CM plus MET/ cease.10 The evidence collected to date regarding the CBT intervention may therefore improve long- term treat- long- term benefits of CM has been mixed. Many studies ment outcomes partially through the potentially compli- that have found a benefit at treatment end fail to find mentary benefits of CM and MET/CBT as standalone an effect at follow- up.11 12 However, other studies have treatments, but second through combinatory effects, found a benefit at 6 months or more post-treatment. 11–15 such as CM improving engagement with MET/CBT treat- At best, if CM does produce significant benefits following ments compared with MET/CBT alone. treatment cessation, it is inconsistent and appears to be The aim of the present review is to evaluate whether present in only a minority of trials. In a systematic review substance use is improved by treatment end and by post- of CM trials published between 2009 and 2014, Davis et treatment follow- up in CM when combined with another al1 identified 69 trials, of which 28 included at least one formal, evidence- based psychotherapy, such as CBT, follow- up assessment post- treatment. Of these, only eight compared with CM alone. found a lasting benefit of CM. Furthermore, while CM is often the most effective during treatment, other inter- ventions more consistently produce long-term benefit. In a recent Cochrane review by Minozzi et al16 of psychoso- METHODS cial interventions for psychostimulant use, CM resulted Design in the clearest evidence of significant reduction in use The Preferred Reporting Items for Systematic Reviews 23 by treatment end. However, at longest follow- up, CM and Meta- Analyses (PRISMA) statement was followed. produced no benefit compared with treatment-as- usual. The protocol was registered on PROSPERO (number 24 CBT meanwhile was associated with significant reductions CRD42017025625). A search of the Cochrane Data- in use (risk ratio=1.89, 95% CI 1.18 to 3.02). As such, it base of Systematic Reviews, the Centre for Reviews and appears that while CM is more effective during treatment, Dissemination’s (CRD) database of reviews and PROS- there is evidence that the benefit from other evidence- PERO found no published systematic reviews or proto- based psychotherapies appears to have less of a drop-off cols of planned reviews that were similar. This study was post- treatment. conducted by a team based in University College London copyright. CM is now often viewed as a method of enhancing comprised of academic and clinical researchers. motivation to abstain using extrinsic rewards. That is, ‘to enhance and maintain initial motivation to abstain from Literature search (substance) use by providing a structure (weekly urine Studies were identified by performing a keyword and http://bmjopen.bmj.com/ testing) and incentive (vouchers) for doing so’.17 This subject search of the following electronic bibliographic contrasts with many other structured psychotherapies.18 databases: MEDLINE, PsycINFO and EMBASE using Ovid A central aim of MI and MET, for instance, is to improve SP, as well as Scopus (Elsevier), Web of Science (WoS) and patients’ intrinsic motivation to change substance Cumulative Index to Nursing and Allied Health Litera- use by exploring and resolving patients’ ambivalence ture (CINAHL). Databases of clinical trials were searched around their substance use and building commitment to for completed and ongoing trials, which were Cochrane abstain.19 Meanwhile, CBT, which is frequently combined Central Register of Controlled Trials (CENTRAL), Inter- in MI/MET in trials of psychotherapy treatment for national Standard Randomised Controlled Trial Number on October 12, 2020 at UCL Library Services. Protected by substance misuse, aims to assist