Decreased gray matter concentration in the insular, orbitofrontal, cingulate, and temporal cortices of cocaine patients

Background: Structural deficiencies within limbic and prefrontal regions may contribute to the characteristic drug-seeking and drug-taking behaviors that prevail in persons dependent on cocaine. To date, a focal structural analysis of the brains of cocaine patients has not been undertaken. Methods: We used voxel based morphometry in conjunction with statistical parametric mapping on the structural magnetic resonance images of cocaine-dependent (n = 13) and cocaine-naive individuals (n = 16) to assess differences between the two groups in gray and white matter concentration. Results: We report a decrease in gray matter concentration in the ventromedial orbitofrontal, anterior cingulate, anteroventral insular, and superior temporal cortices of cocaine patients in comparison to controls (p < .01 corrected for multiple comparisons). The average percentage decrease in gray matter concentration within a region ranged from 5% to 11%. White matter concentration did not differ between groups. Conclusions: We conclude that the brains of cocaine patients are structurally dissimilar from those of nondrug-using controls. The differences were detected in regions involved in decision-making, behavioral inhibition and assignation of emotional valence to environmental stimuli and, hence, may contribute to some of the behavioral deficits characteristic of chronic cocaine users.