to me it sounds like it starts during the trip, but by the end of the song he's been out of it for so long that he's been committed.. or maybe during his trip he became violent, telling people he was the chosen one, etc.. i've known people who were sent to the hospital while on acid, and if you're really out of control they sometimes do strap you down and pump you full of thorazine.. it's supposed to counteract the acid, but according to one friend it did not work at all and actually caused even more vivid hallucinations..

so then as "character" in the song is lying strapped to the hospital bed, he tries to remember the revelations given to him by his visitors or whatever.. which anyone who's had enough experience with hallucinogens can tell you, is quite relatable.