The persistent use of cocaine and other substances by patients receiving methadone substitution therapy is greatly reducing the efficacy of this intervention. Community-based treatment programs are in need of new and effective strategies to enhance the therapeutic potency of methadone treatment by reducing the use of cocaine and other drugs that typically accompany heroin use. Two types of abstinence-oriented behavioral reinforcement procedures have shown considerable promise in achieving increased abstinence rates that will undoubtedly translate into improved treatment retention in this population. The first is contingent voucher incentives (CVI), which offers monetary-based vouchers contingent on submission of drug-free urine specimens. The second approach is behaviorally contingent pharmacotherapy (BCP), in which continued access to methadone maintenance among poorly performing patients is contingent on attending intensified weekly counseling and subsequent submission of drug-free urine specimens. This project will compare the efficacies of these two treatments and will assess the extent to which they complement and enhance one another. The proposed 6-month randomized clinical trial (with a 3-month follow-up) utilizes a 2 x 2 factorial design to systematically evaluate the independent and combined efficacy of these behavioral reinforcement interventions on treatment outcomes (e.g., treatment retention, objective and self-report indexes of drug use, and HIV drug use and sexual risk behaviors) of new admissions to a methadone substitution program in a community-based clinic.
The specific aims of this study are to: 1) compare the relative effectiveness of CVI-only and BCP-only approaches for improving the treatment outcome of new admissions; 2) determine whether combining these approaches (CVI and BCP) is more effective than CVI-only, BCP-only, or a standard treatment intervention; 3) determine the stability of outcome for these interventions during a 3-month follow up period; and 4) determine the associations between individual difference variables (antisocial personality and other psychiatric disorders, indexes of drug use severity, gender and other demographic characteristics) and treatment outcomes. The study will meaningfully extend past research by evaluating the combined and complementary efficacy of these two empirically tested interventions by directly comparing their independent efficacy. It also targets a wider spectrum of drugs of abuse and assesses outcome over a longer duration of time than in previous studies. Since the project will be conducted in a community-based treatment program it also has the potential to enhance the generalizability of study findings to patients in other community-based programs.
