Ok, this one is of a more serious nature. Altered state can be brought about not only be drugs, but also by intense meditation... and incantations. I want to relate about one of my own experiences brought about by Vedic incantations.
A powerful Holyman out of sheer kindness taught me an incantation. I checked out the Sanskrit verses and considered the incantation or
mantra to be incorrect from a grammatical sense. All my life I had been a doubting ass
. Anyway, after six years, out of desperation to
catch a glimpse of the astral world, I decided to try out the mantra. I arranged for a clean empty room, sat down for japa (repeated incantation) on a clean blanket upon the floor. I faced East as prescribed. I started at 12 midnight and completed 6000 incantations by sunrise. During the incantations, my mind became quite empty, only the mantra could be heard inside my head. I repeated this for 3 days and nothing extra-ordinary happened during the sessions. I was pretty frustrated and blamed the faulty mantra (and the ignorance of its sourse, the Holyman) for my failure. As tradition commands, the Yogi should go on practicing with unswerving faith and concentration, without giving a single thought to success or failure. :D That is so... not easy!
Anyway, on the dawn of the sixth day, a really peculiar thing happened. I had completed the incantation for the night, and was putting things back to places... cleaning up the room. Then I laid down for the some rest. Suddenly an irregular blotch of white light came out of the wall and headed straight for me. All my strength vanished, muscles all over my body stopped obeying my frantic commands...
I was paralysed and helpless... to top it all, my breathing stopped! Only my eyes worked, I looked fixedly at the light and started to ask for help with the same incantation. The light passed slowly over me and entered the opposite wall. Slowly my breath returned, then after two minutes, I could move my hands and feet.
Inference: Due to the incessant repetition of the mantra for long hours at a stretch, which is not a normal human behavor, my mind slowly entered an altered state. On the sixth day, I became conscious of some form of
energy and that trauma pushed my bodily functions to a shutdown, temporarily. After that, I stopped the practice and never again witnessed such a light.