Anything's possible, I suppose. No one has the right answer to psychosis yet. Just theories and hypotheses. Personally I think there isn't one right answer. There are so many different experiences, I think we're looking at more than one "illness," probably with more than one cause.

I don't believe in spirits myself, but I'm humble enough to acknowledge that I could be wrong. Maybe if I'd experienced it myself, I'd be a believer.