not really 99%, more 99.9%

the only time when you as a person should never take psychadelics is when you have a pychoaffective disorder (or a history of it in your family) as it can trigger psychosis

other dangers come from heavy abuse of the substances, nothing you can do accidentally (psychadelics are non-addictive chemically speaking, but we humans can abuse anything so there's been cases of it) or taking the substances when you're depressed or anxious (can turn into a bad trip, cure you of those in a day, or just be a normal trip, it's a gamble)

99.9% of the time people who take psychadelics come back to normal after the effects wear off. even bad trips can be beneficial. the normal becomes broader, and many lessons are learnt, the useful hallucinations gain more meaning. i often compare psychadelic trips to having a mirror put in front of yourself and being forced to look at it for hours, now - do you like what you see?