There are no such things as spirits lol and it is funny how anti drug people can be, for no real rational reasons. Most things we consume interact with our brain including tea & coffee, alcohol and even foods. There is an odd perception about 'drugs', a whole blanket list of chemical interactions that people will label as dangerous just because it is a 'drug' that isn't yet sold on a shelf.
DMT as with all drugs, can worsen any pre existing psych condition and it is ill advised for those people. But it does not cause psychological insult.
It does raise neuro sympathetic drive though (fight & flight) so increased heart rate, resp rate, blood pressure etc. But so does a can of red bull!
My perception based on my background in medicine is that DMT trips are just potent dreams,. DMT which is used in memory organisation during sleep, is part of associating sounds, vision and memory along with emotion with the days events. Hence dreams! DMT is released during this process. High doses seem to provide vivid highly sensual experiences that most who try it seem to relish. I believe they are simply experiencing a very potent observation of their brain making associations and new neuronal connections. Nothing to be scared of or even real.
For the physiology involved and background I have, I would love to try it, there is science to be learned from DMT, I really belive think so. Also it looks great fun.