Voucher-based reinforcement of opiate abstinence during methadone detoxification.
Methadone detoxification is often used in the treatment of opiate dependence. This procedure, however, is frequently associated with continued opiate use, and high rates of attrition and relapse. In this study, a 90-day methadone detoxification was enhanced by adding voucher-based reinforcement of opiate abstinence before, during and after the dose tapering schedule. After 4 weeks of standard methadone maintenance (baseline), subjects were randomized to either the abstinence (n=26), or attendance reinforcement (n=22) condition. During the remaining 22 weeks of the study, the abstinence reinforcement group could receive vouchers with monetary value three times per week for providing opiate-negative urine specimens, while subjects in the attendance reinforcement group received vouchers of equal value for attending the clinic, regardless of urinalysis results. Methadone maintenance continued during weeks 5-10, dose tapering was implemented during weeks 11-23, and during weeks 24-26 the voucher schedule remained in effect but no medication was provided. Fifty percent of clients in both groups completed dose tapering, and 40% completed the vouchers-only phase. Subjects in the abstinence as compared with the attendance reinforcement group had lower rates of opiate use during the maintenance and detoxification phases, and longer periods of opiate abstinence during the detoxification phase. Cocaine use was also lower in the abstinence than the attendance reinforcement group during the maintenance and detoxification phases. In addition, abstinence as compared with attendance reinforcement subjects reported significantly fewer intravenous injections during the detoxification phase. Voucher-based reinforcement procedures could be useful for successfully transitioning patients into opiate antagonist therapy, or drug-free treatments.