Increased brain radiodensity in alcoholism. A co-twin control study.

Significantly increased brain density was found in the frontal lobes and caudate and thalamic nuclei of monozygotic twins who were severely dependent on alcohol when compared with their normal-drinking co-twins. No significant differences in brain radiodensity were found in a group of identical twins who were discordant for less severe alcoholism. Hemispheric differences in brain density were also examined. Right-handed normal twins had greater density in the left caudate than in the right caudate region; this difference was reduced but still present in alcoholics.