Fair enough; I wasn't aware that there was a difference. I've always thought that a person's "character" is "the aggregate of features and traits that form the individual nature of some person or thing"[0], but it looks like the most common usage only refers to concern moral/ethical characteristics.

To be clear, I'm not singling out people with mental illnesses; as a person with a physical illness, I would have considered it to be one of my "character flaws".

[0]: http://dictionary.reference.com/browse/character