Publish date: Aug 2016
Contingency management (CM) is a behaviour modification intervention which reinforces desired behaviours through incentives. CM trials have targeted abstinence from drugs as well as treatment adherence (for example appointment attendance, retention and hepatitis B vaccinations). CM is typically used as a psychosocial intervention alongside other treatment interventions such as methadone maintenance to improve treatment outcomes. There are different methods of CM reinforcement including low value cash incentives, voucher incentives, prize-draw methods and clinic privileges. A typical example of a CM programme would be supermarket vouchers awarded to service users receiving methadone maintenance treatment for provision of drug-free urine samples.
CM is recommended by NICE to promote abstinence from illicit drugs and improve engagement with services for those in methadone maintenance programmes. CM has not been routinely implemented into services in the United Kingdom (UK), however it has been implemented and evaluated in the United States. Studies have reported a number of barriers to implementation including reservations from staff around increased workloads, ethical considerations and potential damage to staff-client relationships (McQuaid et al., 2007). Additional organisational barriers such as lack of resources (training and costs) are a challenge for implementation.
Two meta-analyses (Benishek., 2014 & Prendergast., 2006) have reported that CM improved drug use outcomes, although the magnitude of effect decreases over time. The evidence is strongest for treating opiate and cocaine use. Trials are also examining the effectiveness of CM for other substance abuse treatment. Of note, CM has been shown to improve completion of hepatitis B vaccination in people undergoing treatment for heroin dependence (Weaver et al., 2014). CM also shows evidence for improving attendance at appointments (Milward et al., 2014) and improving outcomes for marijuana dependence (Litt et al., 2013). CM is also showing promise for methamphetamine and alcohol users. However, there is not currently enough evidence to draw firm conclusions.
The use of CM in substance-abuse patients has raised some ethical, ideological and practical concerns from clinicians and services. There has been discussion that rewards typical of CM may undermine intrinsic motivation, and may therefore not improve treatment outcomes beyond the CM intervention. Equally, the concept of rewarding drug-users for not taking drugs, may sit uncomfortably with some, particularly in light of society’s perceptions (and stigma) towards drug users. Finally, financial objections have been raised in that it is too expensive to implement CM, although cost-effectiveness analyses somewhat dilute this argument.
CM continues to be evaluated in the UK and, together with the support of NICE we would expect for CM to gradually become part of substance abuse treatment, although implementation barriers may delay this process.
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The opinions expressed in this commentary reflect the views of the author(s) and do not necessarily represent the opinions or official positions of the Society for the Study of Addiction.