My impression is that while LSD and more familiar psychedelics alter the normal brain activity in some fashion or other, DMT works at a more fundamental level that alters brain chemistry to such an extent that it does not function as a thinking brain for a large part of the time (well at least not for me). Imagine that the part of your brain responsible for speech is connected to the part responsible for breathing, and the coordination part to your ears, and visuals to bowels, and that sort of thing -- completely differently arranged. The resulting state is distinctly alien, and goes someway to explaining to me what the absolute limits of psychosis must be before one actually ceases to be able to think.
i'll pass
