Abnormalities in reward processing in drug addiction: Lessons from neuropsychology and neuroimaging studies

Drug addiction is characterized by compulsive drug use despite detrimental consequences to the individual’s functioning as associated with increased salience attributed to the drug and drug-related cues at the expense of nondrug- related reinforcers. Underlying mechanisms include neuroadaptations of the dopaminergic striato-prefrontal circuit to intermittent and chronic supraphysiological stimulation by drugs that increase reward thresholds and decrease sensitivity to reward. This chapter summarizes behavioral and neurobiological evidence for decreased valuation of nondrug reinforcers and cues in individuals with chronic drug use or addiction. It is recommended that future research directly compares between responses to drug and nondrug-related stimuli in addicted individuals. The goal is to devise novel strategies to normalize reward processing, thereby decreasing anhedonia and increasing the motivation to attain alternative nondrug reinforcers, in addicted individuals.