This article reports on an evaluation of the effectiveness of a drug abstinence-based contingency management intervention as an addition to usual care in community treatment settings.
Contingency management interventions that provide tangible incentives based on objective indicators of drug abstinence are effective in improving outcomes in substance abusers, but these treatments have rarely been implemented in community-based settings. The current evaluation examined the effectiveness of such a community-based program. The evaluation used random assignment to usual care or usual care plus abstinence-based incentives for 12 weeks. The focus was eight community-based outpatient psychosocial drug abuse treatment programs. Outcomes were measured for 415 cocaine or methamphetamine users beginning outpatient substance abuse treatment. All participants received standard care, and those assigned to the abstinence-based incentive condition also earned chances to win prizes for submitting substance-free urine samples; the chances of winning prizes increased with continuous time abstinent. The main outcome measures were retention, counseling attendance, total number of substance-free samples provided, percentage of stimulant- and alcohol-free samples submitted, and longest duration of confirmed stimulant abstinence. Participants assigned to the abstinence-based incentive condition remained in treatment for a mean ± SD of 8.0 ± 4.2 weeks and attended a mean ± SD of 19.2 ± 16.8 counseling sessions compared with 6.9 ± 4.4 weeks and 15.7 ± 14.4 sessions for those assigned to the usual care condition (P<.02 for all). Participants in the abstinence-based incentive condition also submitted significantly more stimulant- and alcohol-free samples (P<.001). The abstinence-based incentive group was significantly more likely to achieve 4, 8, and 12 weeks of continuous abstinence than the control group, with odds ratios of 2.5, 2.7, and 4.5, respectively; however, the percentage of positive samples submitted was low overall and did not differ between conditions. The abstinence-based incentive procedure, which provided a mean of $203 in prizes per participant, was effective in improving retention and associated abstinence outcomes. (publisher abstract modified)