Employment-based abstinence reinforcement as a maintenance intervention for the treatment of cocaine dependence: post-intervention outcomes

Abstract

Aims: Due to the chronicity of cocaine dependence, practical and effective maintenance interventions are needed to sustain long-term abstinence. We sought to assess the effects of long-term employment-based reinforcement of cocaine abstinence after discontinuation of the intervention.

Design: Participants who initiated sustained opiate and cocaine abstinence during a 6-month abstinence reinforcement and training program worked as data entry operators and were randomly assigned to a group that could work independently of drug use (control, n = 24), or an abstinence-contingent employment (n = 27) group that was required to provide cocaine- and opiate-negative urine samples to work and maintain maximum rate of pay.

Setting: A non-profit data entry business.

Participants: Unemployed welfare recipients who persistently used cocaine while in methadone treatment.

Measurements: Urine samples and self-reports were collected every 6 months for 30 months.

Findings: During the employment year, abstinence-contingent employment participants provided significantly more cocaine-negative samples than controls (82.7% and 54.2%; P = 0.01, OR = 4.61). During the follow-up year, the groups had similar rates of cocaine-negative samples (44.2% and 50.0%; P = 0.93) and human immunodeficiency virus risk behaviors. Participants' social, employment, economic and legal conditions were similar in the two groups across all phases of the study.

Conclusions: Employment-based reinforcement effectively maintains long-term cocaine abstinence, but many patients relapse to use when the abstinence contingency is discontinued, even after a year of abstinence-contingent employment. Relapse could be prevented in many patients by leaving employment-based abstinence reinforcement in place indefinitely, which could be facilitated by integrating it into typical workplaces.

Trial registration: ClinicalTrials.gov NCT00249496.

Figure 1

Percent of cocaine-negative samples collected at intake (Study Month 0), the end of the abstinence initiation and training phase (Study Month 6), during employment (Study Months 12 and 18), and at post-treatment follow-up (Study Months 24 and 30). Missing samples were counted as positive. The asterisk indicates that the groups are significantly different (p < .05) based on GEE analysis.

Figure 2

Dichotomous results of cocaine urinalysis for individual participants at four time points. The left panel shows the results for the abstinence-contingent employment group, and the right panel shows results for the employment-only group. Rows represent individual participants and columns represent time points. In each panel, the two columns to the left of the vertical midline represent data obtained during the year of employment (Study Months 12 and 18), and the two columns to the right of the line show represent follow-up data obtained after the discontinuation of the study (Study Months 24 and 30). Filled squares indicate cocaine-negative urine samples, open squares indicate cocaine-positive samples, and blank spaces indicate missing data. The numbers on the vertical axes correspond to participant numbers reported in DeFulio et al. (2009).