Isn't that a bit of a disingenious thing for your T/pdoc to say, given that (1) psychiatric categories are substantially arbitrary anyway, and (2) schizophrenia and DID in particular are only so recently separated that nobody really agrees where one ends and the other begins?

Also, if you're doing well without drugs (regardless of your diagnosis) and you're suddenly switched to a diagnostic category where drugs are perceived as required, that doesn't necessitate that YOU take the drugs.