I'm not surprised to see in this thread that it sounds great at the time to play whilst stoned, but that the recordings tell a different story...
Personally, I would rarely even have alcohol when performing, and certainly nothing else whatsoever, as full concentration is required.
When I was an undergraduate there was plenty of stoned playing around, though. I recall a popular singer who claimed he could never remember the lyrics unless he'd had "a couple of pints and a bucket," which is presumably the condition in which he spent most of his time. A local rehearsal studio was run by a chap who dealt pot as a sideline so there were usually jazz woodbines being passed around.