It is interesting for a while, Nick, but truth be, it's a self-indulgence to use the products of someone's illness in order to support one's suspicions about reality.
That being said, though, I'll partially tell an anecdote of a patient I interviewed one night, which does cross over into the realm of an alternate reality. He was a walk-in, probably in his early 30's. His trouble wasn't any major tier mental illness - he was a substance abuser. He had been in and out of detox and rehab for using crack. He was seeking treatment, and told a wild story, worried that he had become psychotic or "crazy". I've told this story before, and it strikes me now that I never should have, ethically. So I'll move onto my own experience of it.
While he was telling his story, I saw spirit all around him --- in that case, a host of tiny sparkly lights. I couldn't tell him (or anyone) that I saw this, but I 'knew' that the story he was telling was real. As per his desire, I got him admitted, and all was well. I did not read his chart, but I speculate with confidence that the doctor wrote up his reported experience as a drug-based hallucination.
I was forbidden to acknowledge any other reality than the consensual one in that setting, but I'll go so far now, in my cranky curmudgeon-ness, as to say that it is not helpful to a psychotic patient to go into his delusion with him, in any setting. I could give many reasons, but I am so far away from my old clinical persona that I feel nauseated at the prospect of getting preachy. It's like another life.