As has been mentioned, the effects of the putative drug and the
indirect effects of lifestyle (esp nutritional) cannot be easily
separated. However, there are several well-known degenerative
disorders of the CNS clearly associated with the chronic use
Wernicke-Korsakoff syndrome is perhaps the best known. The Wernike
part of the syndrome refers to cerebellar atrophy. The clinical
syndrome is a permanently unsteady, or ataxic, gait. It can be
easily seen on MRI as widening of the cerebellar sulci. Korsakoff's
usually refers to a permanent psychosis, appearing later in the
course of the disease. The structural correlate has been suggested
to be mamillary body degeneration (again easily seen with MRI).
Marchiafava-Bignami disease is a rare disorder seen almost exclusively
in male alcoholics and represents degeneration of the middle portion
of the corpus callosum. The pathologic change is demyelination, but
the direct cause is unknown.
Central-pontine myelinolysis is often seen in the treatment of alcoholics
but is now not believed to be due to the direct effect of alcohol.
It is currently presumed due to rapid changes in electrolytes which
occurs when an alcoholic enters the hospital for some related or
unrelated reason and is found to have abnormal electrolyte concentrations
which are then rapidly corrected. If this happens, parts of the pons
demyelinate and the person may be left with a "locked-in" syndrome --
conscious but unable to move any part of the body except the eyes.
Finally, "cerebral atrophy" is commonly observed on CT-scans of alcoholics.
CT shows enlargement of the ventricles and deepening of the sulci.
Again whether it is alcohol or a combination of factors is unknown.
School of Medicine
Univ of Calif, San Diego