Antipsychotics decrease connectivity in the brain to allow psychosis to decrease (Along with everything else - Which sucks) but as time goes on, neurogenesis happens (Especially if you're under 25) to cause a crystalized contact with reality.

Withdrawal of the antipsychotics increase connectivity in the brain to more than it was before you started them, worsening psychosis (Withdrawal psychosis) so neuroplasticity happens to make the psychosis a more crystalized psychosis so when you start the antipsychotic again, it's less likely that the antipsychotic will work.

If you use a psychedelic while in antipsychotic withdrawal, it causes neuroplasticity AND neurogenesis to a previously crystalized state of psychosis, causing irreversible psychosis and schizophrenia.