Employment-Based Addiction Pharmacotherapy

General Therapeutic Workplace Procedures The study was conducted in a model therapeutic workplace in which employment-based reinforcement contingencies are arranged to promote therapeutic behavior change. All participants were invited to attend the workplace for four hours every weekday to work on training programs that were almost fully automated. Participants earned vouchers that were exchangeable for goods and services in the community. Earnings were based on attendance in the workplace and performance in the training programs. Overall, voucher earnings were arranged such that participants could earn a base pay of $8.00/hour for the hours worked in the workplace plus approximately $2.00/hour for their performance on the training programs, for a total potential wage of $10/hour. Detailed descriptions of the therapeutic workplace, the web-based training programs, the staffing requirements, and the cost of the intervention can be found elsewhere. Participants in the Prescription group were eligible to work and earn vouchers independent of naltrexone consumption and/or drug use, however Contingency participants were only permitted to work when naltrexone consumption was objectively confirmed.

Assessment Procedures Assessments were conducted at study intake and every 30 days throughout the study. Primary assessment measures included the Addiction Severity Index-Lite to evaluate changes in medical, employment, alcohol, drug, social, legal and psychological functioning; the opiate, cocaine, alcohol and nicotine sections of the Composite International Diagnostic Interview to evaluate psychiatric disorders; the Risk Assessment of Behavior to evaluate HIV-risk behaviors; and the Beck Depression Inventory-II and Symptom Checklist-90 to evaluate psychosocial functioning. Additional measures were collected.

Naltrexone is contraindicated for patients with hepatic damage or reductions in liver functioning, and is rated in the FDA pregnancy category C. Therefore, blood samples were taken at intake, and months 1, 2, 3, and 5 for liver function (aminotransferase) levels, and pregnancy tests were conducted monthly. Naltrexone was discontinued permanently for one Contingency and one Prescription participant, and temporarily for one Contingency and one Prescription participant due to abnormal aminotransferase levels. Naltrexone was discontinued for one Contingency participant due to pregnancy.

Urine samples were collected under same-sex staff observation upon arrival to the workplace every Monday, Wednesday, and Friday and at each 30-day assessment. Urine samples were analyzed immediately onsite for evidence of opiates (morphine, >300ng/ml), and cocaine (benzoylecgonine, >300ng/ml) using an Abbott AxSYM® fluorescent polarization immunoassay system. Samples collected at 30-day assessments were also analyzed for evidence of buprenorphine, methadone, amphetamine, benzodiazepines, and naltrexone. Urine samples were analyzed for naltrexone using an Enzyme Linked Immunosorbent Assay (ELISA) procedure; values <5ng/ml were considered negative for naltrexone (Friends Laboratory, MD). Participants were informed of their urinalysis results but there were no consequences for positive test results.

Participants were instructed to notify study staff of any adverse events they experienced as soon as possible after the occurrence of the event. Any staff member who was notified by a participant of a potential adverse event filed a formal report into an automated system, which immediately distributed the reports to study investigators and key staff. Ongoing or unresolved adverse events were also included in a weekly adverse event report that was distributed to study investigators and key staff. At all 30-day assessments study staff assessed new adverse events and attempted to resolve any ongoing or unresolved adverse events. Participants were referred to medical staff to receive treatments and concomitant medications as needed, and reports were filed with the Institutional Review Board (IRB) and funding agency in accordance with the relevant institutional requirements and guidelines.