Yo! I've been having a bit of trouble with a school research topic about this, mainly what parts of the brain are affected when you have some alcohol for sleeping and different kinds of stuff. Anything would help whether its personal experience or a link to a specific study.
According to my psychology course, alcohol is a depressant that causes pleasant feelings with only 1 or 2 drinks. Drinking more than this delays reaction time and decisions. Using alcohol severely can result in damage to the part of the brain that is responsible for short term memory(which I believe is the prefrontal cortex) and serious health issues.