Separate and interactive effects of cocaine and alcohol dependence on brain structures and metabolites: quantitative MRI and proton MR spectroscopic imaging.

The effects of chronic cocaine and alcohol abuse on human brain structure and metabolites are not fully known. We studied controls (n = 13) and abstinent subjects dependent on cocaine (8), alcohol (12), and cocaine and alcohol (17) using quantitative MRI and proton MR spectroscopic imaging. Talairach-based techniques yielded tissue and CSF volumes and gray- and white-matter concentrations of N-acetylaspartate (NAA), creatine and choline metabolites in multiple brain regions. Alcohol dependents had lower gray-matter NAA concentrations and more sulcal CSF than non-alcohol dependents throughout the brain. They also had less subcortical gray matter and (regionally) less white matter. Cocaine dependents compared with non-cocaine dependents had higher posterior parietal white-matter creatine concentration. They also had less gray and white matter in the prefrontal lobes and in a region encompassing the temporal lobes and cerebellum. Structural white-matter deficits in cocaine dependents were greater with longer duration of cocaine use. Subjects with concurrent cocaine and alcohol dependence had less prefrontal white matter, especially in the anterior cingulate, than subjects dependent on only one substance. Chronically abused cocaine and alcohol each leave multiple metabolic and structural brain defects after long-term abstinence. Concurrent dependence on both substances may aggravate white-matter structural defects, primarily in frontal brain.