Well, admittedly I’m not the end-all-be-all of information, as I don’t have either DID or schizophrenia. However, I do have a close friend who has both, and from their experience this is what I’ve gathered:
-Schizophrenia does not have alters, or multiple identities residing in one system ((body)).
-DID isn’t characterized by hallucinations, I believe.
-Alters and hallucinations are super duper different.
-Someone with schizophrenia often remembers their hallucinations or can even realize they are hallucinating, whereas people with DID typically don’t remember when another alter in the system is in control.
To anyone with DID or schizophrenia: If I’m mistaken on any of this, feel free to correct me as needed! Again, this is information that I have gotten from my friend, who has resurfacing DID, and is in remission from schizophrenia.