I have this pretty consistently, through waking life. I find that the hypnagogic (or psychedelic) states are conducive to greater complexity, greater volume, a greater number of layers, or some other enhancement/exaggeration of the music that plays normally, though. I can change the music at will, but it's always better to just leave it playing (though I probably seem weird, subtly banging my head everywhere I go!).
High enough doses of cannabis develop the music to the point where it is physically impossible to play - the rhythm sections are Dragonforce solos, as are the vocal lines, while there are three or four drum tracks and actual guitar solos which are faster than the vocal lines. This is one reason why I smoke weed - I fucking love listening to this stuff! It's like communing with God, only Metal as fuck.