It's not at all uncommon for people to not at all enjoy cannabis with psychedelics. I absolutely love pot on a psychedelic comedown (and in general), but smoking at the peak has given me some tense and crappy trips until I learned not to be dumb. I have also seen it put a person into a full blown bad trip, hospital material.

That didn't do anything permanently, but if you've ever had a serious bad trip you'll know that the lingering effects last for some time. And yes, in certain individuals, it could last for a very long time.

Someone can have "underlying conditions" and be leading a normal life. Everyones brain is different and everyone has learned to use the brain they were dealt in a different way.