There seem to be two different talking points here and I think we should separate them. First is the one that psychedelics affect neuro-chemistry in a radical

There seem to be two different talking points here and I think we should separate them. First is the one that psychedelics affect neuro-chemistry in a radical way. We can also include the radically different perspectives here. I can confirm the perspective changes based on personal experiences. However there are also studies which track serotonin increase, and studies which document perspective changes in terminally ill patients. Are these really something you're doubting though? If so, I can dig up some of the papers. Second, and I sense this is your main concern, is that people go crazy from this. I haven't seen any studies about this and don't have any personal experience with it. However I can definitely imagine gullible people going crazy with the experiences. The same kind of people who join Scientology and whatnot. They stop being self-critical and start imagining crazy reasons why their experiences are happening. My point being that the going crazy part is a sperate issue from having psychedeleics cause radical neuro-chemistry changes and providing you with different perspectives.