White matter disruptions in male cocaine polysubstance users: Associations with severity of drug use and duration of abstinence

- Cocaine polysubstance users showed lower white matter integrity compared to controls.
- Mainly disruptions in frontal-striatal and frontal-limbic tracts.
- Results direct to greater white matter integrity with longer abstinence.

BackgroundCocaine dependence has been associated with alterations in the brain's white matter integrity, yet relevant questions remain about what alterations are linked to cocaine use and/or polysubstance use, and whether they are amenable to abstinence.MethodsThis study applied a single measurement session of diffusion tensor imaging (DTI) to examine white matter structure in male cocaine polysubstance users (n = 37) versus male healthy controls (n = 38), along with correlations between DTI measures and patterns of polysubstance use and duration of abstinence. Specifically, we conducted voxel-wise analyses of fractional anisotropy (FA) in the corpus callosum, frontolimbic, striatal and cingulate tracts relevant to drug sequelae.ResultsCocaine polysubstance users, compared to controls, showed lower FA in the body of the corpus callosum, anterior cingulate, uncinate fasciculus and retrolenticular part of the internal capsule. Duration of cocaine use had a marginal negative association with FA in the corpus callosum, and duration of alcohol use was negatively associated with FA in the internal capsule and the uncinate fasciculus. Duration of cocaine abstinence was positively correlated with FA in the uncinate fasciculus, posterior cingulate and fornix-striatum. In the context of cocaine polysubstance use, chronicity of cocaine use is therefore likely to be associated with lower FA in the corpus callosum, and chronicity of alcohol use with lower FA in the frontal-striatal and frontal-limbic tracts. Longer abstinence was correlated to greater FA in frontal-striatal and frontal-limbic tracts, though the direction of causality remains unclear.ConclusionSince the results did not survive multiple comparison-corrected thresholds, more studies are needed to confirm these indications.