Inhibitory-control training for cocaine use disorder and contingency management for clinic attendance: A randomized pilot study of feasibility, acceptability and initial efficacy.

Background: Cocaine abusers have impaired inhibitory Cocaine use is associated with impaired inhibitory control. This study determined the feasibility, acceptability, and initial efficacy of inhibitory-control training to cocaine or neutral images in cocaine use disorder patients.

Methods: Participants were randomly assigned to inhibitory-control training to cocaine (N = 20) or neutral (N = 20) images. Feasibility was assessed by percent of patients eligible for participation after a behavioral qualification session, time-to-target enrollment, percent of clinic visits attended, percent of participants who completed 80 % or more training sessions, and percent of follow-up visits attended. Acceptability was determined using a Treatment Acceptability Questionnaire. Initial efficacy was determined during training and a follow-up phase with urine samples tested qualitatively and quantitatively for cocaine. Participants in both conditions received monetary incentives delivered on an escalating schedule for clinic attendance.

Results: The groups were well matched and no differences on demographic or substance use variables were observed. Attendance was stable during the treatment period with high overall attendance in both groups (average sessions attended: cocaine image group = 97 %; neutral image group = 90 %). No group differences were observed in the percentage of follow-up sessions attended (95 % for the cocaine-image group; 88 % of neutral-image group). Ratings on the Treatment Acceptability Questionnaire were high (i.e., mean scores ≥ 80 for all items rated on 101-unit visual analog scales). Participants in the cocaine- and neutral-image conditions did not differ significantly in terms of cocaine use during the training nor follow-up phase. Inhibitory-control training improved stop signal performance but not delay discounting.

Conclusion: The procedures were feasible and acceptable. Inhibitory-control training to cocaine images did not reduce cocaine use relative to the neutral image training condition. The inability to detect significant differences in cocaine use across the groups is not surprising given the small sample size. More research is needed to determine the utility of inhibitory-control training for cocaine use disorder. Future trials should determine whether inhibitory-control training to cocaine images augments the efficacy of other behavioral interventions.