This is not clear at all. Albert Hoffman, who discovered and uses LSD, turned 100 years old last year and gave a very lucid talk at his birthday party. I have interviewed ALexander Shulgin, who invented over 200 new psychedelic drugs and tested them on himself, and he is in his 80's and can create palindromes on the fly. Many many things could have induced the changes you saw in "hippies", most prominently among them alcohol. Most of the scientific studies of LSD and psilocybin showed positive cognitive effects from the controlled use of what Hoffman calls a "sacrament." GoNZo raises an excellent point about the distinction between use and misuse In the current context of prohibition, perhaps any use is misuse.-mobius