I'm quite surprised by the answers, actually. VJ I feel very much the same way, I don't consider myself mentally ill at all.
There's a guy across the street that stares out the window all day long from his house. When I eat at the table he just sits there and watches me. When I exclaimed that it was odd, my sister said that he was a mentally ill person. What does that mean these days? Depressed, anxious, or schizophrenic, mentally impaired/retarded? Could he just be housebound, or is unable to live unassisted for some reason? The term seemed very unclear.
I used, and still do, assume that mentally ill means that there is a huge deformity that cannot be reversed in the brain.
Oh, adding to this
I think defining oneself as mentally ill can impair their progress. When I found SPWorld 1-2? years ago (wow I've been on here too long) I immediately thought "Oh, I have a mental illness!" and stopped going to school completely using it as an excuse. Maybe that's just me, lol. But putting a label on it to me makes it seem more irreversible, as it has the danger of becoming a part of your identity.