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Milby J.B., Schumacher J.E., Vuchinich R.E. et al.
Journal of Substance Abuse Treatment: 2008, 34(2), p. 180–191.
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Offering homeless, unemployed people seeking treatment for cocaine dependence access to housing and paid employment if they stay drug-free is a powerful incentive, but adding intensive counselling helps maintain abstinence once the incentives end.
Summary This US trial was one of a series conducted in Birmingham, Alabama with a consistent methodology, each involving homeless men and women generally dependent on cocaine and suffering severe distress but not psychotic, and prepared to enter treatment for their drug problems. The series aimed to disentangle the active ingredients of aiding this difficult-to-treat population to resolve their drug problems and get back on their feet in terms of housing and employment.
In the current study participants were identified at a medical facility serving homeless patients and invited to participate in the study. It entailed them being given a furnished flat with food from week two of the study up to 24 weeks, as long as frequent urine tests showed they had not used alcohol or other drugs. During the first 24 weeks urine tests were conducted three times a week for cocaine, cannabis and alcohol. Participants who had tested positive for these drugs at entry to the study were also tested for benzodiazepines, opiates, and amphetamine but with no contingencies attached. Earnings (explained next) paid the study housing's modest rents in weeks nine to 24, before which it was free. From weeks one to 24 participants also had access to vocational training and employment with pay rates Starting pay of $1.25 increased daily to a maximum $5.25 per hour if urine tests were neither missed nor positive and the worker complied fully with workplace guidelines (ie, arrived on time, completed shift, and was non-confrontational). Failing on any of these counts meant pay was reduced to the starting rate and the same contingencies were re-applied. dependent on abstinence. Sustained abstinence qualified participants for follow-on public housing.
Additionally, a randomly selected half of the participants were allocated to an intensive day care programme aiming to help them set and achieve objectives In five common problem domains: addiction; homelessness; unemployment; non-drug-related social and recreational activities; and mental/health and emotional problems. to improve their lives in ways which could be expected to buttress their recovery. Attainment of milestones was rewarded with shopping vouchers. Further counselling Consisting of: a daily patient-conducted morning meeting; emotional processing group; drug and alcohol education; relapse prevention; anger management and assertiveness training; role playing; rational evaluation of mood and emotions; relaxation and stress management training; healthy decision making; healthy communication; healthy self-esteem; weekend planning; recreational outings organised within the treatment context; and recreation/art therapy. In addition, clients met with their individual counsellors for about an hour or more each week. helped them resolve personal and emotional problems and develop coping skills.
The main issue was whether adding day care could further improve outcomes when the participants were already subject to powerful employment/housing incentives. During the 24 weeks these incentives were applied, day care participants were only slightly and non-significantly more likely to be abstinent at any point or to sustain abstinence. But after incentives ended, their abstinence rate declined more slowly than that of incentives-only participants. The result was that on both measures, day care resulted in significantly higher abstinence rates in last year of the study. The authors concluded that for this caseload, employment/housing rewards and punishments on their own were a viable initial intervention, and that intensive day care might be reserved for participants who did not respond well to these contingencies or with co-morbidities such as serious mental illness.
commentary The key finding that combining day care with incentives improved abstinence However, it is unclear to what degree participants substituted other drugs for the ones being tested. Also, using abstinence as the outcome fails to reflect what may nevertheless be clinically significant changes in the intensity of drug use. Within wide limits, urine tests are insensitive to such changes. outcomes had previously been confirmed in reverse – by adding incentives to day care, rather than day care to incentives. Adding incentives substantially improved retention and abstinence outcomes and led to smaller but still worthwhile gains in housing and employment In both cases, by the end of the incentive programme at six months around 20% more participants in the combined intervention were housed or employed, though only the housing figures met conventional standards of statistical significance. rates. An important difference is that in the earlier study, once the added incentives had been withdrawn, associated abstinence, housing and employment gains eroded until one year after treatment entry there was little difference between the groups. In contrast, in the featured study abstinence gains from adding day care became more apparent after incentives ended.
Both studies left open the possibility that simply providing housing and employment assistance, but without abstinence requirements attached, might have been just as effective. For the housing component, this was tested by the same research team in a study which supplemented day care and paid employment opportunities with housing which was either dependent on abstinence, or provided regardless of the participant's substance use. Even while this was in place, requiring abstinence to qualify for housing increased abstinence rates consistently but only slightly. Across the 25 weeks, participants in the group whose housing was threatened by substance use were consistently more likely to be abstinent, but on average the difference was just a few per cent and across the study fell just short of being statistically significant. Neither did it further improve housing or employment outcomes compared to day care only, or to this plus no-strings housing.
Another US research team has investigated the impact of making employment dependent on abstinence, but among a different population – unemployed patients living in poverty in Baltimore who despite being maintained on methadone continued to inject and used cocaine/crack. They volunteered for a data-entry and keypad skills training/work programme remunerated by shopping vouchers. Half were randomly allocated to have access to the workplace (and therefore to pay) only if they submitted a cocaine-negative urine test. The other half were also tested, but the results made no difference to their access to work. This regimen lasted six months. During that time patients required to be abstinent were less likely to use cocaine or to inject, but non-users were still in the minority. Most continued to use cocaine and probably as a result, they spent far fewer days at work and earned less money than patients not required to be abstinent, who also tended to make greater progress in their training. Also the abstinence gains were transitory. Six months after the programme ended, if anything it was the patients who had not been required to be abstinent who were more likely to be cocaine-free. They were also less likely to be trading sex, sharing injecting equipment, or patronising shooting galleries, though by his stage nearly all the diffidence between the two groups were minor and all were statistically insignificant.
The combined implication of these studies is that among these poor, unemployed, and largely black In the US context, commonly a marker of severe relative poverty and disadvantage. populations enmeshed in illegal drug use, work and housing incentives can help initiate and extend drug-free periods, but intensive support is needed to maximise and maintain the benefits once incentives are withdrawn. Without this, the gains from making housing and work dependent on abstinence rapidly erode, and it is unclear whether the long-term benefits justify disrupting the housing and employment stability of patients subject to the contingencies. This disruption is consequent on requiring abstinence in a population for whom this is a very high hurdle. In the featured study, even with intensive support and after a programme lasting from 7.30am to 4pm four days week plus a half day, by the end of the follow-up period most participants continued to use alcohol or other drugs. It also seems that offering decent, affordable housing, substantial employment assistance, and paid employment itself, but without requiring abstinence, has in the longer term been just as effective as making these benefits contingent on abstinence, though the evidence is sparse.
The featured study faced several challenges common to contingency management programmes. Most studies have only documented the limited period Typically 12 weeks. during which incentives were in place. Through this window, the approach seems very effective. But extending the view to the post-incentive period reveals that participants often quickly reverse towards to their previous behaviour. This is not inevitable but it is common, a contrast with approaches like cognitive-behavioural therapy which develop skills and lifestyles in patients which in several studies seem to become more securely embedded as time passes. This may be partly because impacts are typically limited to the targeted behaviours and/or the targeted drugs. Effectively, people do what is needed to get the rewards or avoid the punishments, potentially leaving other relapse-precipitating features of their lives ready to exert their influence once the programme ends. Overcoming this by extending the intervention may be impractical, and may in any event not work; unlike other interventions, in general the longer a contingency management programme runs, the weaker its effects. Another limitation is that such programmes are most feasible and work best when they target a single drug, yet many patients use several to excess. Targeting all these risks setting the bar so high that many patients do not experience the incentives. Even with simpler regimens, patients commonly qualify for none of the rewards or are subjected to sanctions because they do not exert the required control over their behaviour. The risk is that the most vulnerable, unstable and severely dependent participants are further disadvantaged, either missing out altogether or being repeatedly 'knocked back' as they fail to sustain the required standards.
Other studies have attempted to mitigate these risks by enabling incentives to be earned through smaller steps, rewarding recovery-promoting activities rather than or as well as abstinence, and by combining contingency management with programmes which address the individual's psychological or social vulnerabilities. The featured study tried several of these tactics. Within the contingency management regimen, recovery-promoting vocational and employment-related activities were financially rewarded, while psychosocial vulnerabilities were addressed by pairing the incentives with intensive day care. Whether the more severely dependent or unstable patients were relatively disadvantaged is not reported. We know from an earlier study in the series that a quarter of the participants offered intensive day care and housing/employment incentives did not control their substance use sufficiently to qualify for any rewards.
Based on a recommendation from the National Institute for Health and Clinical Excellence (NICE), contingency management programmes are now being trialled in British drug treatment services. Government welfare-to-work plans incorporate a 'contingency management' type element At this time the plans are going through the parliamentary process. See http://www.dwp.gov.uk/mediacentre/pressreleases/2009/jan/drc124-140109.asp. This element of the plans is being resisted by the Scottish government (Macleod A. "SNP rejects plan to cut benefits for drug addicts" The Times: 14 December 2008 http://www.timesonline.co.uk/tol/news/uk/scotland/article5342246.ece). in the form of reduced benefit payments for problem drug users who do not engage with and make progress in the rehabilitation plan agreed with (or determined by) their employment adviser. These moves take Britain closer (but still quite distant) to a policy context in which the type of programme tested in the featured study might be feasible and acceptable.
If contingency management does become prevalent in Britain, much will depend on the particular form it takes. The evidence is strongest for rewarding desired behaviour and this is the approach staff and patients may be most comfortable with, but it risks a public and media backlash. Punishing undesired behaviour is less effective and risks counterproductive side effects, but may be more acceptable to the broader public. Another alternative is to reward good behaviour by removing punishments, but this has not been adequately researched.
Thanks for their comments on this entry in draft to Tim Leighton of Action on Addiction's Centre for Addiction Treatment Studies. Commentators bear no responsibility for the text including the interpretations and any remaining errors.
Last revised 24 February 2009
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REVIEW 2009 Efficacy of opiate maintenance therapy and adjunctive interventions for opioid dependence with comorbid cocaine use disorders: a systematic review and meta-analysis of controlled clinical trials