Tangenty tangent: The thing is, there are real people who have* multiple personalities, not all of whom identify as mentally ill**. There is no way this storyline is going to be done well by their lights. And I'm too used to seeing autism completely misrepresented to enjoy seeing other conditions misrepresented.

* Or claim to have, but as a general principle I assume people are honest about their own mental experiences. I don't need to understand it on a personal level, no more than I need to understand being transgender or gay or NT or whatever.

** That is, they function well in the real world and don't want to be fixed.