This should lead to a longer, richer conversation. In my master's psychology program, we were of the humanistic orientation and rejected diagnostic labels altogether, including for schizophrenia.

Throughout my doctoral program, I asked a simple question; "What is mental health?"

Nobody has a clear answer. If you can't define mental health, you can't define mental illness. Generally, the response for what is mental illness is, "if it causes significant impairment."

I was just talking to a friend who would be, if he submitted to it, diagnosed bipolar, who says he has to be mindful of his ups and downs otherwise things can get difficult.

But if you happen to have a sweet tooth, you need to mind your various compulsive behaviors otherwise over consumption of sugary substances could make life difficult. Does that mean you're mentally ill?

It may sound strange, but in traditional Indian medicine, there's nothing quite parallel to our modern notion of "mental illness." (The very IDEA of something mental as an "illness" is philosophically deeply confused, in fact - part of the mind-body confusion which pervades the mental health field, and really, all of science).

Take a look at Ayurveda. Even if you think it's nonsense, they're take on human psychology, health and sickness, at least may inspire some radically different ideas.