Randomized trial of continuing care enhancements for cocaine-dependent patients following initial engagement

The effects of cognitive-behavioral relapse prevention (RP), contingency management (CM), and their combination (CM + RP) were evaluated in a randomized trial with 100 cocaine-dependent patients (58% female, 89% African American) who were engaged in treatment for at least 2 weeks and had an average of 44 days of abstinence at baseline.

The participants were from intensive outpatient programs, which provide 10 hr per week of group counseling. The CM protocol provided gift certificates (maximum value $1,150; mean received = $740) for cocaine-free urines over 12 weeks on an escalating reinforcement schedule, and weekly individual RP sessions were offered for up to 20 weeks. Average number of RP sessions attended was 3 in RP and 13 in CM + RP.

Generalizing estimation equation analyses over 18 months postrandomization showed significant effects for CM (but not RP) on urine toxicology and self-reported cocaine use (p = .05), with no significant CM x RP interactions. Secondary analyses indicated CM + RP produced better cocaine urine toxicology outcomes at 6 months than treatment as usual, odds ratio [OR] = 3.96 (1.33, 11.80), p < .01, and RP, OR = 4.89 (1.51, 15.86), p < .01, and produced better cocaine urine toxicology outcomes at 9 months than treatment as usual, OR = 4.21 (1.37, 12.88), p < .01, and RP, OR = 4.24 (1.32, 13.65), p < .01. Trends also favored CM + RP over CM at 6 months, OR = 2.93 (0.94, 9.07), p = .06, and 9 months, OR = 2.93 (0.94, 9.10), p = .06. Differences between the conditions were not significant after 9 months.

These results suggest CM can improve outcomes in cocaine-dependent patients in intensive outpatient programs who have achieved initial engagement, particularly when it is combined with RP.