I had a bit about memories in uni last year that I half remember. before memories form properly, doing other things with your brain can make them weaker. it's the reason you're supposed to study before sleeping. alcohol reduces brain activity, so they're not overwritten. it helps you forget the past in the present, and the present in the present, and the present in the future, and helps you remember the recent past in the future.
vitamin b1 deficiency is often found in alcoholics because they get bad nutrition, and makes you forget the past in the present and the present in the future, then you make up new ones, but they're boring.