Syd Barrett

Syd Barrett was the founding member of the psychedelic rock group, Pink Floyd, but he left the band in 1968. Barrett has a history of well-documented mental illness usually associated with his extreme drug abuse. In response to questions about Barrett's drug abuse, David Gilmour, guitarist and singer of Pink Floyd, said, "his nervous breakdown would have happened anyway. It was a deep-rooted thing. But I'll say the psychedelic experience might well have acted as a catalyst. Still, I just don't think he could deal with the vision of success and all the things that went with it." Barrett's mental illness inspired Pink Floyd's 1975 album, Wish You Were Here. His influence can be seen in the title of the two part song, Shine On You Crazy Diamond.
http://www.youtube.com/watch?v=vyqgjCKm9nQ