Neural circuit mechanisms of the cholecystokinin (CCK) neuropeptide system in addiction

•Cholecystokinin (CCK) remains understudied as a neuropeptide modulator in addiction.•CCK is expressed in limbic reward nodes of the extended amygdala circuitry.•We cover findings implicating CCK activity and receptor signaling in drug intake.•Indications of sex differences in CCK expression and corresponding drug effects.•Neurotechnology advancements can modernize understanding of CCK in addiction.