I always have a few beers at band practice and often a little weed too. I figure that if you're playing at a bar, you're gonna be in that state so you better be able to play in that state (if you've ever witnessed a drunk band who clearly never drink at practice...yeah...) I don't get DRUNK though, just a buzz, enough to get outta my own way...if I let my brain into the equation I start to suck more!
I wasn't playing back in the days when I did psychedelics so I don't know how that would affect my playing and I don't really care to find out...I do find that over a certain amount of beer/weed my retention is poor...
my before bed ritual is a beer in the evening, a joint and some melatonin; otherwise my brain rarely turns off and I don't sleep...sadly I've been an insomniac since my preteen years; the number of times people thought I was nuts and I really just hadn't slept for three days...