I am bipolar.

For me its not a negative perception either, I'm far more than a diagnosis, but it has definitly played a major role in shaping the woman I've become, and its not all bad either.

I guess its just how I speak, "I am" comes way more naturally than "I have", and since the former doesn't come with any negative connotations, I see no reason to change it.

Also, I do feel weird when I try saying I have, because I didn't get infected with it or inherit it from anyone and I sure as hell can't cure it.