This might seem an odd question, however out of personal curiousity, are there any documented accounts of amazing feats by players while in an altered state of consciousness? What I'm looking for would be something like attempts at drunken, blind, simultaneous chess.
I don't know if this counts, but here is a story (unfortunately only in Norwegian) about the former president of the Norwegian Chess Federation, Jøran Aulin-Jansson, who in his youth played blitz for 92 hours straight: http://www.nrk.no/sport/92-timer-med-sjakk-i-strekk-1.6589371
In 92 hours and 26 minutes he played 701 games and won 549 with 32 draws.
He explains how accidentally eating a rotten chicken kept him awake during the third night.
At one point he hallucinated about spiders crawling up his leg. I guess that qualifies as "altered state of consciousness".
For blindfold chess, the record is playing 46 games at once:
In 1947 GM Miguel Najdorf, while sitting in an isolated room, played 45 games simultaneously in São Paulo, Brazil. In another room his opponents sat with regular boards and pieces in front of them, and their and Najdorf’s moves were transmitted to each other via standard chess notation using a microphone. This performance exceeded his own previous world record of 40, set in 1943 in Rosario, Argentina. Until a few weeks ago, since 1947 only one player had played as many as 35 blindfold games at once under well-controlled conditions. That successful master was Marc Lang of Günzburg, Germany, who handled 35 opponents in November of 2010, surpassing blindfold champion George Koltanowski’s still-existing European and pre-Najdorf world record of 34 simultaneous games set in Edinburgh in 1937 (in 2009 Lang had set a new German record of 23). Lang’s only remaining goal was to exceed Najdorf’s 45 games and thereby gain the world record. For the past year he has been preparing to do just that, which he accomplished by playing 46 opponents on November 26-27, 2011.
Tal wrote in his biography that once he had a complex adjourned position and that night he dreamed the solution while sleeping. When he woke up, he remembered the dream and knew what to do. He wrote that this was the only time such a thing had ever happened to him.
Playing chess while under the influence of recreational drugs or alcohol generally has very bad results, speaking from experience. You generally play at a significantly lower level. The only exception is that sometimes a very small amount of alcohol, like one drink, can sometimes be beneficial because it calms you down a little bit. So, if you are all wound up and nervous before a tournament game, a beer can be the antidote.
Chess games and matches played while drinking alcohol in particular are easy to find if you go back in history a bit. The one that immediately comes to mind are the matches between La Bourdonnais and McDonnell in 1834 in which La Bourdonnais won despite reportedly spending much of his time between moves drinking, smoking and gambling on other games. Perhaps this is not a 'feat' in the same manner as a massive simul or so on, but these were arguably the two strongest players in the world at the time and so could be considered a de-facto world championship match.
And also as in one of the comments to the OP, Alekhine also played many of his games while drinking heavily, apparently including his 1933 World Championship match.
Paul B., Good question. I'm possibly a 1000 rated player on a good day, fingers crossed. A few decades ago I was playing the black pieces against an unbeatable cafe player. I'd dropped acid. Five moves into the game, he suggested I move my Bishop to b4. Then I started peaking, and I absolutely annihilated him - felt vibrating ley lines humming from all the squares and pieces. I knew with absolute certainty that I couldn't lose. Best game I've ever played, and the odd thing was that I beat the second-best player twice the next evening...?
Sigh. Hick town, no chess here, not willing to drop acid and have elderly freakout even though, whew, I live next door to a trauma center...yuk, yuk.
In short, you never know about mind expanding drugs and chess, (in fact the mind is endless,) but wow-what a ride!!!