Quote from : Why Does He Do That?: Inside the Minds of Angry and Controlling Men Book

ALCOHOL HAS NO BIOLOGICAL CONNECTION TO ABUSE OR VIOLENCE Alcohol does not directly make people belligerent, aggressive, or violent. There is evidence that certain chemicals can cause violent behavior — anabolic steroids, for example, or crack cocaine — but alcohol is not among them. In the human body, alcohol is actually a depressant, a substance that rarely causes aggression. Marijuana similarly has no biological action connected to abusiveness.