A lot of people say psychedelics and schizophrenia are contraindicated but there isn't much to suggest it's true. You won't find any research linking the two, you will find some stuff like childhood schizophrenia being treated by LSD/psilocybin in the 60s/70s, and lots of research disconnects 5HT2A (main psychedelic receptor) from schizophrenia, this research occurred because they thought it was involved and wanted to prove it, but got just the opposite.
I've got a family history of schizophrenia and was psychotic for a few years, but mushrooms are fine for me. It's cannabis that makes me crazy.
Saphris will really strongly block 5HT2A receptors and also cause them to downregulate since they're being used constantly (same thing as tolerance).
If you wanted an antipsychotic onboard and you still wanted to trip, you'd have to look at Solian, Seroquel (both which are really weak at serotonin receptors) and the second generation antipsychotics like flupenthixol which are also quite weak at serotonin receptors.
Stopping cold turkey will cause some bizarre, nightmarish, feverish dreams and probably some general distress during the day.