Decreased brain metabolism in neurologically intact healthy alcoholics

Objective: The extent to which cerebral dysfunction in alcoholics is related to the direct effects of alcohol in the brain rather than to indirect mechanisms and/or alcohol withdrawal remains unclear. The purpose of this study was to evaluate whether healthy alcoholics with no evidence of alcohol-associated complications showed changes in brain glucose metabolism. Method: Positron emission tomography and [¹⁸F]-fluorodeoxyglucose were used to measure regional brain metabolism. The study group consisted of 22 normal, healthy, right-handed volunteers and 22 neurologically intact, healthy, right-handed alcoholics tested 6 to 32 days after alcohol discontinuation. Results: Alcoholics showed significantly lower whole brain metabolism than normal control subjects. Normalization of regional metabolic values to the whole brain metabolic rate revealed that the left parietal and right frontal cortices were the most affected regions. Although the whole brain metabolic rate was correlated with the amount of time since alcohol discontinuation, the "normalized" decreases in left parietal and right frontal glucose metabolism were not. Conclusions: These findings support the contribution of the direct effect of alcohol as well as alcohol withdrawal on the changes in regional brain metabolism seen in alcoholics. They also provide evidence of cerebral changes in neurologically intact healthy alcoholics.