Depersonalization and derealization are truly awful. Having experienced them for non-psychedelic reasons, it's almost indescribable.
Sometimes people say "seeing events in third person". My experience was that my consciousness and actions were completely disconnected from my observations of reality. Like, I questioned whether I had any influence at all over my existence. Basic, predictable events were suddenly uncertain and terrifying. It left me with no mental capacity to do anything but uneasily exist.
With treatment, it goes away gradually over months. I never want to go back there.
It definitely depends on the person and the state of mind they have when they go into it. I've had really overwhelming de-personalization episodes on LSD as well and they were extremely positive, life transforming experiences. I had studied and practiced Buddhism for years prior to having those experiences, though, which helped me integrate what was happening. It was like all of a sudden getting a direct experience of what was previously just words and philosophy -- "oh, this is what he was talking about."
Had I gone into it totally blind with no way to frame it it probably would have been a nightmarish scenario though. There's a reason why Right View (samyak-drishti) is the first of the 8 Noble Truths [1] and the one really emphasized in the beginning of your Buddhist practice.
One wonders if that's how it actually is and the rest is just the brain fooling us into having control by way of rationalizing the actions we were going to do anyway.
We kinda know its like that dont we. Perhaps those who suffer such condition see throuh the abstractions our brain makes. Like seeing things in a rawer form that doesnt align well with more normative views of society.
Without the lies our brain tells our consciousness, we couldn't function. Even core stuff like the way that we see or our experience of choice, are dependent on our brain fooling us in some way.
Luckily, we an pretty good at being hypocritical. This allows us to learn and think about this stuff while still believing the lies.
Sometimes people say "seeing events in third person". My experience was that my consciousness and actions were completely disconnected from my observations of reality. Like, I questioned whether I had any influence at all over my existence. Basic, predictable events were suddenly uncertain and terrifying. It left me with no mental capacity to do anything but uneasily exist.
With treatment, it goes away gradually over months. I never want to go back there.