Abstinence-based incentives in methadone maintenance: interaction with intake stimulant test results.

Baseline drug use detected in urine toxicology has been shown to predict drug abuse treatment outcome, including response to contingency management interventions with drug abstinence as their target. This study examined the association between baseline urine test result and treatment outcome in stabilized methadone maintenance patients with ongoing stimulant use to determine whether abstinence incentives were differentially effective in those testing stimulant negative versus positive at study entry. Participants were 386 methadone-maintained patients who took part in a National Drug Abuse Treatment Clinical Trials Network multisite study aimed at reducing stimulant abuse during treatment (J. M. Peirce et al., 2006). At study intake, 24% of participants tested stimulant negative and 76% tested positive. Those testing negative at entry submitted 82% negative urines during the study versus 36% for those testing positive at entry (odds ratio [OR] = 8.67; confidence interval [CI] = 5.81-12.94). Compared with those receiving usual care, the addition of abstinence incentives resulted in a significant increase in stimulant-negative urine samples submitted during the study both for those testing negative at study entry (OR = 2.27; CI = 1.13- 4.75) and for those testing positive (OR = 1.84; CI = 1.25-2.71). These findings suggest that abstinence incentives have significant clinical benefits independent of initial drug use severity among methadone maintenance patients with ongoing stimulant drug use.