Study Design
Depression
Eligible participants were enrolled in a 30-week randomized clinical trial with thrice-weekly visits. Participants completed a 6-week incentive lead-in period in which monetary incentives were available for evidence of urinalysis-verified cocaine abstinence beginning day 1. Participants who achieved 6 consecutive negative samples (ie, 2 weeks of abstinence) during this period were categorized to a relapse prevention (RP; 20 participants) incentive group. Participants who did not achieve 6 consecutive negative samples during weeks 1 through 6 were categorized to an abstinence initiation (AI; 60 participants) incentive condition. After assignment, participants were stratified separately within each incentive condition via a minimization procedure (Beck Depression Inventory summed total scores from screening; ≥14 vs <14; range, 0-63 and sex) to receive bupropion SR or placebo by the research pharmacist, who had no participant interaction. Participants continued to attend thrice-weekly visits for the duration of the 30-week protocol; urinalysis samples and self-reported cocaine use were collected at every visit. To facilitate data collection, participants received randomly allocated incentives (prize range, $0-$50) for session attendance independent of urinalysis outcomes.