Hi Emma!
There are many documentaries, theories, and literature in general on schizophrenia being a modern manifestation of a psychic, a shaman, a person whose role in society is to venture the many realms of existence..
Indeed, the pineal gland is heavily linked with experiencing these states, as it storages large amounts of DMT (world's most powerful halucinogen) which are released upon death. Schizophrenia is linked to the effects of various hallucinogen drugs, not sure how exactly, perhaps a 'malfunction' of these centres.
These are some of my personal favorite documentaries exploring this idea
I've read that the difference between a shaman and a schizophrenic is that a shaman learns to control it and use it to benefit him/his people, while a schizophrenic struggles with the condition. Western medicine sees it more of a burden while some indigenous/eastern people see it as a gift to be nurtured and used to its potential.
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About experiencing other people's lives, I've had that happen to me. I could switch between people I know and even strangers-- I noticed I had a different body by my swinging hands and I was also located in their homes.