I think you can be mentally ill and know there is a problem. It's called having insight, and it's a pretty good thing, because without that helping ourselves would be pretty hard to do.

Does knowing that you have physical symptoms, and it turns out you have a physical illness make it any less of an illness or problem?

I think it's a very big misconception the mentally ill people lack any insight to know there is something going wrong.

You only really need to start talking to a lot of other people to sometimes realize that it isn't quite a common shared human condition.

I had my first bout of psychosis when I was 11, I really did think it was something we all must experience, but when I finally told my parents, then I realized it was not so. Although they blamed demons and put their hands on me and cast the devil out while speaking in tongues. At that point, and the more I asked around, I did realize this was not the norm.

People can have insight, even into psychosis, and you will see this with psychosis brought on by physical illness as well, but I would not say that it is a chosen behavior.