Apparently he admitted to dropping acid twice a day for two years, or something along those lines. ALthough I don't think that it's one drug in particular that got him the way he is now. He was a young and wild rock star, he had free drugs flying at him from left and right and he just gobbled up any drug that was offered to him. That would fuck anyone up.
The alcohol he abused did more damage than all the drug he took combined. There is a condition in helpless alcoholics called "wet brain" where so many brain cells have been killed, the person is shakey and mumbles and can't think properly. It usually occurs in much older abusers, but Oz did SO MUCH booze that he was probably hit early.
