I don't define my health status by whether or not I'm seeing someone about it (although I am, and in context in the hospital I have no problem saying patient). But context is the whole thing. In identifying myself to someone new I say I have bipolar disorder. Specific and only stigmatizing as far as the word bipolar has been misunderstood. Admittedly a lot.

Saying I have any diagnosis is controversial to a few extremists who deny mental illness, and although I'm not supportive of that idea I do have to talk to them, and write about shared ground with diplomatic language.

A new word? The best neutral word I use in professional talk also works socially - stakeholder. Like it?