Yes alcohol and drug abuse causes brain deterioration. My now deceased brother was an alcoholic all his adult life. Two years before his death, he was diagnosed with alcohol related dementia. He ended up drinking himself by choice to death. Personally I don't touch it -was a minimal social drinker but stopped and didn't like the taste or altered affect it had on me. I have too many unpleasant memories of family members drinking as a child, so I can't stand to be around a drunk person. It can ruin lives and the ripples also affect family and friends.