shows that almost all participants in both groups provided cocaine positive urine samples at intake to the study and cocaine negative urine samples at the end of phase 1. The figure also shows that abstinence-contingent employment participants maintained significantly higher rates of cocaine abstinence during phase 2 relative to the employment only group, but that this difference was not apparent during the follow-up period. Analysis of urine samples collected during phase 2 employment (at the 12- and 18-month time points) showed that abstinence-contingent employment participants provided significantly more cocaine-negative urine samples than employment-only participants [82.7% and 54.2%, respectively; P = .01, odds ratio (OR) = 4.61, 95% confidence interval (CI) = 1.38 – 15.38]. At the follow-up time points, the two groups were not significantly different (P = .93, OR = 0.96, 95% CI 0.37 – 2.52), and the percentage of cocaine negative samples observed during follow up for abstinence-contingent employment (44.2%) and employment-only (50.0%) groups was similar to the proportion of cocaine negative samples observed for the employment-only group during phase 2. As reported previously, opiate use was very low in both groups and not significantly different at any time point throughout the study.
Figure 1 Percent of cocaine-negative samples collected at intake (Study Month 0), the end of the abstinence initiation and training phase (Study Month 6), during employment (Study Months 12 and 18), and at post-treatment follow-up (Study Months 24 and 30). Missing (more ...)
shows individual participants’ cocaine urinalysis results at six-month intervals during the year of phase 2 employment and at the follow-up time points during the year after phase 2. Overall, the figure shows that the pattern of cocaine-negative urine samples of individual participants across the phase 2 and follow-up time points is fairly stable for employment-only participants, whereas it is not stable for abstinence-contingent employment participants. Most importantly, of the ten employment-only participants who provided cocaine-negative urine samples in study months 12 and 18 (i.e., during phase 2), 70% maintained that pattern during follow-up. In contrast, only 30% of the 20 abstinence-contingent employment participants who provided cocaine-negative urine samples in study months 12 and 18 maintained that pattern during follow-up. Statistical analyses confirmed these general observations by showing that the percentage of cocaine-negative urine samples obtained at 12- and 18-month time points were significantly correlated with the percentage of cocaine-negative urine samples obtained at follow-up time points (24 and 30 months) in the employment-only group (P = .001; r = .63), but they were not correlated in the abstinence-contingent employment group (P = .59; r = .11).
Figure 2 Dichotomous results of cocaine urinalysis for individual participants at four time points. The left panel shows the results for the abstinence-contingent employment group, and the right panel shows results for the employment-only group. Rows represent (more ...)
During the follow-up period, self-reported rates of HIV risk behaviors were relatively low in both groups and no significant differences were obtained. No injection drug use was reported by any participant during the follow-up period, and abstinence from crack was reported by 75% and 66.7% of employment-only and abstinence-contingent employment group participants, respectively. We previously reported a significant effect on trading sex for drugs or money during the intervention period, but this difference was not maintained during follow-up; 8.3% and 3.8% of participants in the employment-only and abstinence-contingent employment groups reported trading sex for drugs or money, respectively.
Analyses of the relationship between pre-treatment participant characteristics and post-treatment cocaine abstinence (defined by the submission of 2 cocaine negative samples during the follow up year; Y/N) showed that being younger (Wald χ2(1) 5.39, P = 0.02, OR = 1.17, 95% CI = 1.02–1.33) and male (Wald χ2(1) 4.12, P = 0.04, OR = 0.16; 95% CI = 0.03–0.94) were associated with abstaining from cocaine use during the follow-up period, Income from all sources (including welfare) in the 30 days prior to study participation, completion of HS or GED (Y/N), and days of self-reported cocaine use in the month prior to joining the study were not significantly associated with post-treatment outcome. Analyses of the relationship between baseline measures obtained during the first 30 days of induction in phase 1 (when no contingencies were applied) and post-treatment cocaine abstinence were also conducted. These analyses showed the proportion of cocaine negative samples obtained during this period (missing = positive) was positively correlated with post-treatment cocaine abstinence (Wald χ2 (1) 4.12, P = 0.04, OR = 23.14, 95% CI = 1.11–481.26), but the percent of days attended in the first 30 days of induction was not predictive of post-treatment abstinence.
The data in characterizes social, employment, economic and legal conditions of the lives of participants in the two groups over the course of participation in the study. Overall, the table shows that the lives of participants in the two groups were fairly similar throughout the study. The participants in the two study groups were not significantly different on any of these measures at intake, at the end of training, during the year of employment, or during the year of follow-up. More participants reported earning at least some money from employment during the year of follow-up compared to at study intake, but only about 40% of participants earned any money from employment during the year after employment in therapeutic workplace. Similarly, a lower percentage of study participants were on welfare or living in poverty during the year of follow-up compared to at study intake, but the majority of participants were on welfare and in poverty during the year of follow-up. Social stability indices showed that a large majority of participants were satisfied with their living situation and still in drug treatment during the year of follow-up. Reported rates of illegal activity and new involvement with the criminal justice system were low at all points throughout the study.
EMPLOYMENT, ECONOMIC, SOCIAL, AND LEGAL OUTCOMES