Effects of alcohol and benzodiazepines on brain metabolism: [18F]FDG-PET studies

To further investigate the functional role of GABAergic systems in alcoholism, we applied functional imaging (PET, EEG) with pharmacological challenges to healthy controls, detoxified alcoholics and subjects at risk for alcoholism. Two samples of male controls underwent two or three, respectively, [¹⁸F]FDG-PET studies with simultaneous EEG recording, both before and after challenge with either lorazepam or alcohol. The lorazepam challenge only was applied to alcohol-dependent subjects and subjects at risk for alcoholism. While lorazepam in controls reduced regional cerebral glucose metabolism (rCGM) in occipital cortex and in thalamus, alcohol stimulates rCGM in ventral striatum, frontal cortex, and in diencephalic regions. RCGM was increased in the anterior cingulated and right prefrontal cortex during alcohol influx compared to alcohol elimination. Data obtained in alcoholics and in subjects at risk for alcoholism are currently being investigated. At this point our data indicate that the alcohol effects by far exceed those observed under lorazepam.