Chronic drug use is a defining characteristic of drug dependence.1
Patterns of drug use frequently extend over many years.2-5
However, most treatments have not been designed to address drug dependence as a chronic problem.1
Recognizing the chronic nature of drug dependence, researchers have called for the use of long-term maintenance interventions.1,6
The development of long-term psychosocial interventions is especially critical for cocaine dependence, as no effective pharmacotherapy is currently available.7
Contingency management, in which patients receive desirable consequences contingent on providing objective evidence of drug abstinence, is one of the most effective treatments for cocaine dependence.8-14
Based on overwhelming evidence of the effectiveness of these contingency management interventions, the National Institute for Health and Clinical Excellence recommended their adoption by the National Health Service of the United Kingdom.15,16
Like other treatments, contingency management interventions have not historically addressed the chronicity of cocaine dependence and have typically been applied briefly. Although lasting effects have been noted after short-term exposure,17
relapse is common after discontinuation of the program.14,18
One study showed that cocaine abstinence could be maintained throughout a year-long exposure to voucher-based abstinence reinforcement.19
However, the use of an intervention of indeterminate length involving payment for drug-free urine samples is likely to be cost-prohibitive. A practical vehicle for arranging long-term abstinence reinforcement is required.
Employment-based abstinence reinforcement, in which access to employment is contingent on objective evidence of drug abstinence, has been proposed as an ideal long-term treatment for cocaine dependence, because workplaces control powerful reinforcers and facilitate regular and long-term monitoring of patients.20
Drug testing is used in workplaces, so its use in employment-based abstinence reinforcement programs is consistent with existing workplace practices.21-25
The therapeutic workplace is an employment-based abstinence reinforcement intervention. In the therapeutic workplace, unemployed drug dependent adults are invited to work, and are required to provide drug-free urine samples to maintain access to the workplace and maintain maximum rate of pay. In one randomized trial, pregnant and recently postpartum women in methadone treatment assigned to the therapeutic workplace had significantly higher rates of drug-free urine samples than usual care control participants.26,27
Additional studies showed that employment alone was not sufficient initiate cocaine abstinence, but that employment-based abstinence reinforcement significantly increased cocaine abstinence initiation.28,29
In light of these results, this study targeted two critical questions. First, does short-term exposure to employment-based reinforcement produce lasting abstinence after the abstinence contingency is discontinued? Second, can long-term employment-based reinforcement prevent relapse and maintain abstinence over an extended period of time?
The study was conducted in adults who used cocaine persistently during community methadone treatment. Eliminating cocaine use in this population is of particular public health significance because many of these individuals used crack cocaine and thus were at considerable risk for acquiring or transmitting HIV via high risk sexual behaviors, most notably trading sex for money or drugs.30-32
The study had two phases. In phase 1, all participants were exposed to employment-based abstinence reinforcement to initiate drug abstinence. Participants who initiated abstinence advanced to phase 2 and were hired as data entry operators in a nonprofit data entry business for one year, and randomly assigned to an employment only or abstinence-contingent employment group. Employment only participants worked independent of their urinalysis results, similar to typical employment. Abstinence-contingent employment participants were required to provide cocaine- and opiate-negative urine samples to work and continue earning maximum pay under a routine and then progressively more intermittent random drug testing schedule.
The primary objective of this study was to evaluate the effectiveness of employment-based contingency management in maintaining long-term cocaine abstinence in methadone patients during a year of employment in a nonprofit data entry business. The secondary objectives were to determine if long-term exposure to employment-based contingency management increased opiate abstinence and reduced HIV-risk behaviors. We expected that many participants in the employment only group would relapse to regular cocaine use during the year of employment. In contrast, we expected that sustained exposure to employment-based abstinence reinforcement during employment would maintain abstinence in most participants throughout the year of employment in the data entry business.