Concomitant with prefrontal activation of a craving system that is mediated by glutamate, human imaging studies have reported deficits in executive function that are reflected by decreases in frontal cortex activity that interfere with decision making, self-regulation, inhibitory control, and working memory,109 and might involve disrupted GABAergic activity in the prefrontal cortex (table 2, circuit 13).50 For example, alcoholics exhibit impairments in the maintenance of spatial information, disruption of decision making, and impairments in behavioural inhibition. Indeed, Volkow and colleagues36 and Goldstein and Volkow14 have described a syndrome that is characterised by excessive salience to drug-paired cues, decreases in the responsiveness to non-drug rewards, and decreases in the ability to inhibit maladaptive behaviour. Such frontal cortex-derived executive function disorders in addiction have been linked to deficits in the ability of behavioural treatments to effect recovery.110
