I suppose I've been knocking on heaven's door for about 11 years now, with one sort of high or another. The only kinds of drugs I use, though, are ones that keep me working for longer periods of time. I haven't gotten involved in anything heavy since '68. I had a silly flirtation with smack then, but it was only for the mystery and enigma of trying it. I never really enjoyed it at all. I like fast drugs. I've said that many times. I hate falling out, where I can't stand up and stuff. It seems like such a waste of time. I hate downs and slow drugs like grass. I hate sleep. I would much prefer staying up, just working, all the time. It makes me so mad that we can't do anything about sleep or the common cold.

As quoted in this interview in Playboy magazine (September 1976)