Chronic Cocaine Use and White Matter Integrity: A Diffusion Tensor Imaging Study
Chronic substance use and its effects on brain function and structure has long been of interest to clinicians and researchers. Prior cross-sectional comparisons of diffusion tensor imaging (DTI) metrics have suggested deleterious effects of chronic substance use (i.e., cocaine use) on white matter integrity. However, it is unclear whether these effects would persist when accounting for confounding factors, such as chronic alcohol use, and how improving DTI technologies may enhance detection of substance use-related pathology. In this study, we sought to conduct a replication of previous work in this area and determine whether there are any patterns of persistent differences in white matter microstructure between individuals with a history of Cocaine Use Disorder (CocUD, according to DSM-IV) and healthy controls. 46 participants (21 healthy controls, 25 chronic cocaine users) were recruited from the Richmond, Virginia metropolitan area. Information regarding past and current substance use was collected from all participants. Participants also completed structural and DTI scans. Consistent with previous DTI studies, significant differences were found between CocUD and controls. These differences were in fractional anisotropy and axial diffusivity but not other diffusivity metrics. Lifetime alcohol consumption was greater in the CocUD group, but lifetime alcohol consumption did not show significant linear relationship with any of the DTI metrics in within-group regression analyses. These data align with previously reported declines in white matter integrity in chronic cocaine users. However, it is less clear whether comorbid alcohol consumption results in an additive deleterious effect on white matter microstructure.