Did you not notice Cali's post that people end up with permanent periodic psychotic breaks from hallucinogens, in particular sativa? Not my idea of fun or BS.
You're being serious, so am I. You said you're willing to believe there are things that you don't understand or know about so try this line of reasoning: There are alternative dimensions that exist right next to the world we live in. Some of those universes/realms/worlds are accessible to us, but not in physical form (which is constrained by its nature to this dimension). Our consciousness is permanently anchored to our 3 dimensional bodies until we die but it can travel into different dimensions if a person is born with the innate talent or is trained or gets a boost from nature.
If the wrong person messes around with shamanic plants they can loosen their anchor in this plane. They've opened their consciousness to those alternative dimensions, without knowing how to close it up again.
I'm no expert, I don't claim to be, never have. Maybe if I was an expert I could explain it better ... more likely than not I'd probably not bother discussing this at all because esoteric/occult stuff (I mean that in the literal definition of those words) is something a person is either drawn to and comes to accept or doesn't and trying to talk to the latter about this shit either annoys them or makes them think you're a flake.