Study 1
A study from Cornish and colleagues (1997) looked at the ability of naltrexone therapy to reduce opioid use and reincarceration of Federal probationers with a history of opioid addiction. The study sample included individuals who had been assigned to serve a minimum of 2 years on Federal probation or parole. They were being supervised by probation officers of the Substance Abuse Program of the United States Federal Probation Office in Philadelphia, Pa. Sixty-eight probationers volunteered to participate in the study; 51 of these probationers completed the consent, initial evaluation, and induction into the study. The 51 enrolled subjects were randomly assigned in a 2:1 ratio to the experimental group (n= 34) or the control group (n= 17). The sample was 90 percent male, and 62 percent African American, 24 percent white, and 14 percent Latino, with an average age of 39 years. There were no statistically significant differences between the two groups.
Control group members were required to attend three orientation and counseling sessions each week during the first 2 weeks of the study. The sessions concentrated on obtaining drug use and treatment histories and provided information on AIDS education and risk reduction. Control group members also provided a monitored urine specimen and breathalyzer reading twice a week. During weeks 3 through 24 of the study, the control group saw their probation officer twice a week, and one of the two visits was randomly selected for group members to provide a monitored urine specimen and breathalyzer reading.
The experimental group received naltrexone treatment. Two days before the first scheduled medication visit, group members provided a supervised urine sample to ensure they were not actively using opioids. Group members who were found to be opioid dependent were offered detoxification at an inpatient facility. On the first day, a standard 0.8mg naloxone challenge (intravenous or subcutaneous) was administered to verify the absence of physical dependence on opioids. Experimental group members who had a positive naloxone challenge were asked to repeat the test 24 to 48 hours later. When the naloxone challenge was negative, group members received a 25mg oral dose of naltrexone. If no clinical evidence of opioid withdrawal manifested after 1 hour of observation, they were prescribed naltrexone 25mg daily for 2 days, followed by 50mg daily for 3 days. About 1 week after initiation, they were stabilized on a naltrexone regimen of 100mg on Tuesdays and 150mg on Fridays. This dosage and dispensing regimen was maintained throughout the study period. Once a week the experimental group members provided a directly observed urine sample and a breathalyzer reading from research staff (though these results were not shared with the probation office, and the probation office did not share its results with the research staff). All urine samples were analyzed for 10 substances, including opioids, amphetamines, cocaine, benzodiazepines, barbiturates, and various other sedatives, using the enzyme multiplied immunoassay technique. Study retention was determined by counting the number of weeks that group members remained in compliance with the treatment protocol. Those who had 2 consecutive weeks of absences were dropped from the study.
The study lasted 6 months, which was consistent with naltrexone treatment protocols of earlier clinical studies. Study participants were scheduled to meet with their probation/parole officer weekly for the first 6 months. Medication visits were scheduled for twice a week, with one visit scheduled to occur the same day as a probation office visit (the treatment office was across the hall from the probation office).
The outcomes of interests included opioid use, which was measured by positive urine samples, and reincarceration rates. The study used t–tests and chi-square tests to determine the significance of the differences between the experimental and control group outcomes. Only 52 percent of the experimental group remained on naltrexone for the entire study period. The highest rate of dropout occurred during the first month of the study (the majority occurred within the first week). Thirty-three percent of the control group was retained through the entire study. The retention rate for the experimental group was not significantly higher than that of the control group.
