It was stated that similar effects can been felt with alcohol.
Funny thing is I say to people who take drugs that everyone is looking to feel good, to feel better, to feel at peace and happy within themselves.
The truth of this is that everyone is thus trying to be spiritual. Thus drugs give that momentary spiritual feeling, that high. But alas it's via a physical means. Heavy training, alcohol, drugs, all physical means of trying to feel spiritually well in self.
Irresponsibility. Just be your spiritual self and depend on nothing else. Ha, ha.
I agree everyone is looking for a pleasant feeling of well-being, and would guess it is at the root of all behavior. I come from a natural religion point of view in which the physical is spiritual. This isn't to say mind-affecting substances are always "spiritual activities," however, and I agree it's better to be able to induce these states without need of external catalysts. I will say, however, that I had a moment one time in my early 20's where I suddenly gained insight into how depressed I was and it came about from an "external catalyst." So, ultimately I think the most important part of an experience has to do with what you do with it afterward; how it continues to affect personal development...but again, to reinforce the ideal: I agree; depend on nothing apart from your own mind-body.