Persons recovering from addiction must refrain from drug use even when the opportunity to use exists. Understanding how behavioral response to drug reward opportunities is modified is key to treating addiction. Most effective behavioral therapies encourage patients to increase reinforcement opportunities by engaging unidentified sources of nondrug reward. The authors integrate transdisciplinary research on the brain and behavioral effects of increasing reward availability to demonstrate one neurobiological mechanism by which behavioral therapies help patients abstain. Explicating neurobiological processes underlying psychotherapy provides predictions about the interaction between dopaminergic medications and therapy and the impact of individual differences in dopamine receptor expression on addiction vulnerability.