Monitoring cocaine use and abstinence among cocaine users for contingency management interventions.

During contingency management interventions, reinforcement of cocaine abstinence is arranged by delivering an incentive when a urine sample tests cocaine-negative. The use of qualitative versus quantitative urinalysis testing may have important implications for effects on cocaine abstinence. Qualitative testing (i.e., testing that solely identifies whether a particular substance is present or absent) may not detect short-term cocaine abstinence because a single instance of cocaine use can result in cocaine-positive urine over many days. Quantitative testing (i.e., testing that identifies how much of a substance is present) may be more sensitive to short-term cocaine abstinence; however, the selection of a criterion for distinguishing new use versus carryover from previous use is an important consideration. The present study examined benzoylecgonine concentrations, the primary metabolite of cocaine, in urine samples collected three times per week for 30 weeks from 28 cocaine users who were exposed to a cocaine abstinence contingency. Of the positive urine samples (benzoylecgonine concentration >300 ng/ml), 29%, 21%, 14%, and 5% of the samples decreased in benzoylecgonine concentration by more than 20%, 40%, 60%, and 80% per day, respectively. As the size of the decrease increased, the likelihood of that sample occurring during a period leading to a cocaine-negative urine sample (benzoylecgonine concentration ≤300 ng/ml) also increased. The number of days required to produce a cocaine-negative sample following a positive sample ranged from 1 to 10 days and was significantly correlated with the starting benzoylecgonine level (r = 0.43, p < 0.001). The present analyses may aid in the development of procedures that allow for the precise reinforcement of recent cocaine abstinence during contingency management interventions.

Economic cost of the therapeutic workplace intervention added to methadone maintenance.

Therapeutic workplace is a novel intervention that uses access to paid training and employment to reinforce drug abstinence within the context of standard methadone maintenance. We used the Drug Abuse Treatment Cost Analysis Program as a standard method of estimating the economic costs of this intervention. In a 1-year period, the therapeutic workplace served 122 methadone maintenance clients who had a median length of stay of 22 weeks. The workplace maintained a mean daily census of 48 clients. The combined cost of methadone maintenance and the therapeutic workplace was estimated at US$362 per week. This cost is less than that of other treatments that might be used to promote abstinence in individuals who continue to use drugs during methadone treatment. Given prior evidence of effectiveness, these cost data may be useful to policy makers, social service agencies, and researchers interested in using or further developing the therapeutic workplace intervention.

Attendance rates in a workplace predict subsequent outcome of employment-based reinforcement of cocaine abstinence in methadone patients.

This study assessed whether attendance rates in a workplace predicted subsequent outcome of employment-based reinforcement of cocaine abstinence. Unemployed adults in Baltimore methadone programs who used cocaine (N=111) could work in a workplace for 4 hr every weekday and earn $10.00 per hour in vouchers for 26 weeks. During an induction period, participants provided urine samples but could work independent of their urinalysis results. After the induction period, participants had to provide urinalysis evidence of cocaine abstinence to work and maintain maximum pay. A multiple regression analysis showed that induction period attendance was independently associated with urinalysis evidence of cocaine abstinence under the employment-based abstinence reinforcement contingency. Induction period attendance may measure the reinforcing value of employment and could be used to guide the improvement of employment-based abstinence reinforcement.

A randomized controlled trial of the therapeutic workplace for community methadone patients: a partial failure to engage.

The Therapeutic Workplace is an employment-based treatment for drug addiction that uses wages for work to reinforce drug abstinence. The Therapeutic Workplace has promoted abstinence from heroin and cocaine in treatment-resistant mothers in methadone treatment. This study attempted to replicate that effect in crack cocaine users recruited from community-based methadone programs. Participants were randomly assigned to a Therapeutic Workplace (n=22) or usual care control (n=25) group. Therapeutic Workplace participants were invited to work in the workplace and earn vouchers every weekday for 9 months contingent on documented opiate and cocaine abstinence. The two groups did not differ significantly on measures of cocaine or opiate use collected during study participation. Daily attendance and urinalysis results of the Therapeutic Workplace group were analyzed, and only 7 of the 22 participants initiated consistent periods of abstinence and workplace attendance. Two individuals gained access to the workplace on a few days, and 9 participants attempted to gain access to the workplace but never provided a drug-negative urine sample. Possible reasons for differences between the current study and the previous Therapeutic Workplace study are considered. Procedures that increase participant contact with the Therapeutic Workplace and its reinforcement contingencies might increase the likelihood of these individuals being successful in the treatment program.

Behavioral factors predicting response to employment-based reinforcement of cocaine abstinence in methadone patients.

We sought to identify behavioral factors associated with response to an employment-based intervention, in which participants had to provide drug-free urine samples to gain access to paid employment. The present secondary analysis included data from a randomized clinical trial. The trial evaluated whether employment-based reinforcement could decrease cocaine use in community methadone patients. Participants (N=56) in the trial worked in a model workplace for 4 hr every weekday and earned about $10 per hr. After a 4-week baseline, participants were randomly assigned to an Abstinence & Work (n = 28) or Work Only (n = 28) condition and could work for an additional 26 weeks. Abstinence & Work participants had to provide cocaine-negative urine samples to work and maintain maximum pay. Work Only participants only had to work to earn pay. For Work Only participants, cocaine abstinence during baseline and the intervention period were significantly (rs = .72, p <.001) correlated. For Abstinence & Work participants, baseline opiate abstinence was significantly correlated (rs = .59, p <.001) and workplace attendance was marginally correlated (rs = .32, p = .098) with cocaine abstinence during the intervention period. Furthermore, participants who provided over 60% cocaine-negative urine samples during the intervention period (i.e., responders) had significantly higher baseline rates of opiate abstinence (p <.0001) and workplace attendance (p = .042) than non-responders. Employment-based reinforcement of cocaine abstinence may be improved by increasing opiate abstinence and workplace attendance prior to initiating the cocaine-abstinence intervention.

Disruption of temporally organized behavior by morphine.

Four pigeons pecked keys in two different procedures commonly used in the study of timing, or temporal discrimination. Sessions consisted of 40 trials. During half of the trials, two keys were presented for 50 s. Left-key pecks were reinforced according to a variable-interval 67.86-s schedule during the first 25 s of the trial, and right-key pecks were not reinforced. During the second 25 s of the trial, right-key pecks were reinforced according to the same schedule, and left-key pecks were not reinforced. In the other half of the 40-trial session, the center key was presented. The majority of these trials arranged fixed-interval 2.5-s schedules. Occasionally a probe, or peak-interval, trial was presented. These trials were 100 s in duration and terminated without reinforcement. These two procedures were used to examine the effects of morphine on indexes of timing and on patterns of responding. Morphine altered behavior in a race-dependent manner in both procedures. Low baseline (saline) response rates were increased following morphine administration, and high baseline rates were either unaffected or decreased slightly. Rate-dependent effects appeared as leftward shifts in the timing index for two-key trials and decreases in the index of curvature for fixed-interval trials. Despite large changes in response rates, no consistent shift of the peak time was observed during peak-interval trials. These results are discussed primarily in terms of rate dependency; that is, rates of responding following drug administration tend to be determined in large part by rates of responding under baseline conditions.

Professional demeanor of chronically unemployed cocaine-dependent methadone patients in a therapeutic workplace.

This study assesses the frequency that users of illicit drugs display unprofessional behaviors in an employment setting. This research was conducted in the therapeutic workplace, a model employment-based treatment program for chronically unemployed adults with long histories of illicit drug use in 2003. Fifty-three unemployed adults in methadone treatment, who were opiate and cocaine dependent, showed signs of injection drug use, and recently used cocaine were hired to work for 4 hours every weekday for 7 months. Results show that while the overall incidence of many undesirable behaviors is low, a small percentage of participants had serious workplace behavior problems that might limit their success in community workplaces. This study suggests that unprofessional behavior in the workplace could contribute to chronic unemployment in this population. The study's limitations are noted and future needed research is suggested.