Abstract
Background: Nontreatment-seeking individuals with cocaine use disorder (CUD) have been found to exhibit decision-making on laboratory tasks that is risky but also sensitive to monetary incentive, relative to controls. Objective: The purpose of this study was to replicate these findings in treatment-seeking individuals and explore their relationships with voucher-based treatment outcome and striatal dopamine (DA) release. Methods: This study was approved by the Institutional Review Board, and all participants provided written informed consent to participate. Eighteen briefly-abstinent individuals seeking treatment for CUD and 19 control participants were compared on performance of a modified Iowa Gambling task (mIGT) under both hypothetical and cash earning conditions. The CUD participants subsequently received Positron Emission Tomography (PET) scans with [11C]raclopride with methylphenidate (60 mg) challenge and then 12 weeks of Community Reinforcement Approach plus Vouchers (CRA+V) treatment. Results: On the mIGT, the CUD participants’ advantageous card selection was selectively more sensitive to the presence of a monetary incentive, relative to controls (F4,128 = 3.10, p<0.05). Among the male CUD participants, those who exhibited greater DA release in the ventral striatum (VSt), and those who responded to the CRA+V treatment, exhibited greater mIGT incentive sensitivity than those who were nonresponders (F4,44 = 5.84, p<0.01), and who exhibited relatively decreased VSt DA release (F4,48 = 2.55, p<0.05). Conclusions: Participants seeking treatment for CUD exhibited selectively increased decisional incentive sensitivity, relative to controls. For the male CUD participants, greater incentive sensitivity was associated with greater VSt DA release and better CRA+V outcome. These findings appear partially consistent with previous findings on cognition and motivation in individuals with CUD, and suggest a heuristic model connecting striatal DA, incentive sensitivity, and CRA+V outcome.
Keywords
Cocaine, Iowa Gambling task, Decision-making, Contingencies, Reinforcement, Motivation community reinforcement, Dopamine, Striatum, PET