This is just some random information I'm going to put out, take it if you like. There is a vitamin called Thiamine aka vitamin B1. In the brain glucose is metabolised as energy for brain cells. Thiamine is used by the brain to convert the glucose to energy. Alcohol blocks the bodies absorbtion of Thiamine, so no Thiamine, no energy for the brain, this leads to brain cell death, which causes lesions to form on the brain. For most of us this isn't a big deal as the damage is not severe as we usually replenish B1 from our diets once the alcohol has left our system. But for alcoholics, people with eating disorders, or with ailments of the stomach that might prevent the absorbtion of nutritiants, this can be dangerous. Long term lack of B1 can lead to a condition known as Wernicke-Korsakoff syndrome, also known as wet brain, or alcoholic dementia. The lesions on the brain can cause gaps and breaks in memory, and destroy a person's short term memory completely. This condition is irreversible. Luckily the way to avoid this is good nutrition, dark leafy greens are a great source of B1, plus there are supliments. And as with most things avoidence is better than treatment, so drink sensibly and eat your veg.
(this is just a very wide overview of a complex illness, I've barely scratched the surface of)
Aaron