People who drink alcohol -- even the moderate amounts that help prevent heart disease -- have a smaller brain volume than those who do not, according to a study in the Archives of Neurology.

Overall, the more alcohol consumed, the smaller the brain volume, with abstainers having a higher brain volume than former drinkers, light drinkers (one to seven drinks per week), moderate drinkers (eight to 14 drinks per week), and heavy drinkers (14 or more drinks per week).

http://www.cnn.com/2008/HEALTH/diet.fitness/10/14/healthmag.alcohol.brain.shrinkage/index.html

(It's better with a spliff than with a drink I think.)