Structural and functional characteristics of impulsive-related brain regions in heroin addicts with long-term withdrawal

Abstract

average of 44 months after withdrawal, and the extent of damage was correlated with lifetime dose. (1) Compared to the healthy control group, the heroin group had significantly (a) lower gray matter volume ( p = 0.03) and lower whole-brain volume ( p = 0.05); (b) lower gray matter in the right superior frontal gyrus ( p AlphaSim < 0.01); (c) higher regional homogeneity in right posterior central gyrus and lower regional homogeneity in right middle frontal gyrus of the orbitofrontal cortex ( p AlphaSim < 0.01); (d) lower amplitude of low-frequency fluctuation in right inferior frontal gyrus of the orbitofrontal cortex and left hippocampus ( p AlphaSim < 0.01); (e) higher functional connectivity between right inferior frontal gyrus of the orbitofrontal cortex and the right caudate, and lower functional connectivity between the right inferior frontal gyrus and right middle temporal gyrus as well left precentral gyrus ( p AlphaSim < 0.01). (2) Within the heroin group, higher lifetime dose of heroin was significantly associated with lower gray matter volume in the right middle temporal gyrus and left middle cingulate ( p AlphaSim < 0.01). The results showed that compared to healthy controls, heroin addicts had significant damage in brain structure and functions related to impulsivity even after an average period of 44 months of abstinence. In addition, the extent of damage was correlated with the lifetime dose of heroin. These results suggest that heroin addicts could continue to show impulsive behavior even after several years of abstinence, perhaps explaining the high rate of relapse in this population. Future research could test this conclusion by examining correlations between brain damage in areas related to inhibition and behavioral measures of impulsivity after a period of abstinence. The current evidence underscores the need to take impulsivity into account in relapse prevention programs for heroin addicts.