A recent study published in the journal of Psychiatry Investigation conducted a comprehensive review of all the research since 1971 to 2011 on how alcohol affects cognition. As you might imagine, there are varied results over the years, but overall, there seems to be two different ideas about alcohol and cognition:
2. Light to moderate drinking might provide a protective benefit for cognition. According to the study's authors, "low to moderate drinking (LMD) may be helpful for stress relief, relaxation, mood elevation, intimacy formation, and cognitive function."
Other studies have correlated light to moderate drinking with increased heart health as well. The authors do state that there is not enough clear evidence at this time to recommend low and moderate drinking as a way to prevent dementia, but feel that this is an area that could benefit from further research.