The neurocircuitry of impaired insight in drug addiction

Abstract

More than 80% of addicted individuals fail to seek treatment, which might reflect impairments in recognition of severity of disorder. Considered by some as intentional deception, such 'denial' might instead reflect dysfunction of brain networks subserving insight and self-awareness. Here we review the scant literature on insight in addiction and integrate this perspective with the role of: (i) the insula in interoception, self-awareness and drug craving; (ii) the anterior cingulate in behavioral monitoring and response selection (relevant to disadvantageous choices in addiction); (iii) the dorsal striatum in automatic habit formation; and (iv) drug-related stimuli that predict emotional behavior in addicted individuals, even without conscious awareness. We discuss implications for clinical treatment including the design of interventions to improve insight into illness severity in addiction.

Figure 1

Self-reported pleasantness ratings (A) and objective choice behavior (total picture viewing selections) on an implicit choice task (B) for each of four picture types (pleasant, unpleasant, neutral, and cocaine) for individuals with cocaine use disorders (CUD; N=20), as compared to healthy comparison subjects (HC; N=20). For both (A) and (B), error bars represent standard error of the mean. * p<0.05. Results show that although CUD rated the pleasant pictures as more pleasant than the cocaine pictures (A), providing higher pleasantness ratings than the controls, the CUD's objective choice behavior did not show this effect (here controls chose to view the pleasant pictures more than the CUD, who also did not show enhanced pleasant picture over cocaine picture choice) (B). Adapted with permission from.

Figure 2

A summary of imaging results showing activation of the anterior insular cortex (AIC) during particular tasks and emotions. The two right-hand columns contain images from different studies that found predominantly unilateral activation; images in the two left-hand columns show mostly bilateral activation. Stimuli that activate the right AIC are generally arousing to the body (for example, pain). The left AIC is activated mainly by positive and affiliative emotional feelings. ACC, anterior cingulate cortex. First published in.

Figure 3

Patients who quit smoking after lesion onset and patients who underwent a disruption of smoking addiction after lesion onset and whole-brain region-by-region logistic regression analysis. Pie charts (A) illustrate the proportion of patients in each anatomical group who fell into each of the behavioral categories. Regions (B) for which there was a statistically significant association between a lesion and a disruption of smoking addiction (P < 0.05, uncorrected) are highlighted in red. The insula was the only region on either side of the brain where a lesion was significantly associated with a disruption of smoking addiction. Adapted with permission from.

Figure 4

Regions of brain activity differentiating Aware from Unaware Errors in 16 healthy control subjects and 17 young cannabis users. Bar graphs represent mean BOLD % signal change (relative to baseline) for each group during Aware and Unaware errors. Adapted with permission from.