Our work during the past ten years has established the efficacy of cognitive-behavioral therapy (CBT), alone and in combination with medication, for cocaine dependence. It is now important to explore the extent to which outcomes for CBT can be maximized. Emerging evidence suggests that acquisition of skills through practice of coping skills outside of sessions facilitates better outcomes in CBT; thus, strategies that facilitate completion of homework tasks are likely to improve outcomes in CBT. In addition, disulfiram has been demonstrated through a recent series of randomized double blind controlled trials to significantly reduce cocaine use, particularly in combination with CBT. However, lack of adherence can undercut the effectiveness of disulfiram. Contingency management (CM) approaches are highly effective in their own right as behavioral interventions for cocaine use disorders and can be used to promote other target behaviors, such as compliance with other therapies. CM has not yet been explored as a strategy to enhance outcomes by promoting adherence to CBT or to disulfiram treatment of cocaine dependence.
Specific aims for this Stage II trial are: First, to conduct a 12 week randomized clinical trial, using a 2x2 factorial model, with 160 cocaine dependent outpatients, that will evaluate the efficacy of CBT in combination with either: (1)placebo, (2) disulfiram, (3)placebo plus CM, or (4) disulfiram plus CM. Second, to evaluate the long-term durability and/or delayed emergence of treatment effects after termination of the study treatments through a one-year follow-up. The primary outcomes will be self-reported cocaine use (days of abstinence by week), and results of thrice weekly urine toxicology screens. Compliance with disulfiram treatment will be monitored by the riboflavin tracer procedure. Behavioral treatments will be manual-guided and monitored for therapist skill and adherence to manual guidelines. Follow-ups at 1, 3, 6, 9 and 12 months after cessation of study treatment will assess the durability and/or delayed emergence of treatment effects. Variables assessing theoretical mechanisms of action will be assessed monthly during treatment.
