The impulsivity behavior is correlated with prefrontal cortex gray matter volume reduction in heroin-dependent...

Chronic exposure to heroin induced cerebral structural abnormalities may underlie heroin-related behaviors. The aim of this study was to: (1) identify cerebral structural abnormalities in heroin-dependent individuals (HDIs) by an automated and unbiased morphometric technique. (2) Define the correlation between these cerebral structural abnormalities and the impulsivity characteristic in HDIs.

24 HDIs and 24 control subjects were completed with (1) high resolution structural magnetic resonance imaging scanning and analysis of gray matter volume using voxel-based morphometry implemented in Statistical Parametric Mapping and (2) a Chinese translation Barratt Impulsiveness Scale-11 questionnaire survey. Differences in regional gray matter volume were tested using an analysis of covariance model, co-varying for global gray matter and age. Statistical maps were set at p<0.05, corrected for multiple comparisons. The abnormal brain regions were correlated with the duration of heroin use and impulsivity scores.

After adjusting for effects of age and total gray matter volume, cortical gray matter volume in the bilateral medial prefrontal cortex, bilateral dorsal lateral prefrontal cortex, and right fusiform cortex were significantly reduced in HDIs. Moreover, the gray matter volume in prefrontal cortex that showed group differences was negatively correlated with the duration of heroin use and negatively correlated with the impulsivity characteristic in HDIs.

These findings reveal the prefrontal cortex was impaired in HDIs, meanwhile, indicate the changes in gray matter volume are relating to the duration of heroin use and the impulsivity characteristic of the HDIs.