Some cultures do believe in visions more through basic shamanism. Instead of being in a straight-jacket in a padded room you’d become a member of an elder group. I often wonder how much could be possible. I don’t think I’ve had false memories, but perhaps I’m wrong…most of the time I am.
I’m just as confused as you are. During psychosis I can get a lot of these memories coming up.Thing is a few of the less traumatic memories that have come up I’ve spoken to my mum and found out it was true after all. In one the case of been told around 8-9 my dad was adopted it was never spoken about since until I started bringing it up.
I did start doing some memory work later just moving into counseling. About 6 years ago I think. I was stable and working. while heading to work a few times I started getting memories of going through psychosis as young as 3-4 years old. Pretty much in the car driving down the same road something triggered it off. Extremely traumatic hallucinations more then what I ever faced as a Adult or Teen. I’ve heard it’s possible but extremely rare. I’m also in a rare category of being a child of a Vietnam vet. But would it be possible of you going through psychosis as a child and that’s what your remembering?
I agree that psychosis can definitely come in childhood and traumatic events can lead to illness. Right on!
I have the same thing pretty much. My explanation is parallel universes. I have other ideas too but I’m still in incubation mode lol.
I was in the hospital in early January for 10 days. I was sedated most of that time but have very specific “memories” from being there that never happened. People, names, conversations, places, of things in the hospital that never happened. I also clearly remember traveling outside the hospital to places I’ve never been but unlike a dream, I can still, months later, describe every detail.
In reality, I was restrained to a hospital bed the entire time and none of these memories ever took place. I had pneumonia and not a psychological disorder and there were no strong narcotics involved. It’s definitely one of the strangest feelings of my life but I’ve stopped talking about what I clearly remember before I do get a new diagnosis.
Just to complicate things further - every time you remember a memory, the integrity of the original memory is compromised as your present mentality influences how the memory is stored again. If all memories were READ ONLY, we’d all be much less confused. 
there’s a fascinating book called “Stumbling on Happiness”… by David Gilbert i think?.. discussing how flawed our memories are and how we constantly fabricate memories to make up for our brains’ use of shorthand memory cues.
anyhow. i have false memories in the sense that sometimes i confuse vivid dreams with reality. or i believe i said or did something, when in fact i only thought about, or mentioned those things in conversation.
my childhood is full of false memories, dreams, delusions, and pieces of stories either written or read by my younger self. the only parts i know are true are the ones other people tell me about, and even then, they are telling me their version, not my own. the lack of a substantial photographic record makes this even more difficult. i can look at old report cards and medical documents, and know these things happened, but i don’t remember, except for tiny pieces – like the way the sun looks rising over the sandias mountains. half the time, telling a story, i realize halfway through it is probably a lie.
on the flip side, my actual memory is swiss cheese. i contacted a childhood friend by chance a year or two ago and she told me how i had apparently sent her some very explicit emails and photos? which was very embarrassing and i had no memory of doing it. so then i felt out of my depth, confused, and embarrassed, and just wanted to hang up right away.
i am coming to a point where i am no longer relying on my brain to be truthful at all, and i am constantly seeking validation of memories / thoughts / decisions from others. “did that happen? or am i making it up?”
I get weird false memory flashes of all kinds of things but the most striking are of being kidnapped and tortured as a young child. I was never kidnapped or tortured. It’s very confusing.