My one ex-friend informed me before leaving that my other ex-friends all think I'm "batshit crazy". On reflection I'm not sure a term like "mentally ill" would have fared me much better with this group as I know from past experience around other "crazies" that they simply have a zero tolerance attitude towards it. Even depression is viewed as a character defect. The one guy who most embodies this attitude of this ex-circle once told me, I guess meaning it to be helpful to me somehow "J, [my wife] and I both grew up with big, loving families, so you maybe can't understand this" -- awesome way to begin a sentence to anyone, really -- "but gossiping about our friends is just a normal way to blow off steam..." It got better from there.
I don't like the widespread connotation of "mental illness", even among "sufferers". I think my biggest problem with it is the implication that unlike almost all other types of illness, mental illness is intrinsic to a person, is present (undiagnosed) from birth, and is a permanent trait. The term itself is accurate, but the connotation is so often that it is a root cause, rather than an effect. So everyone in the family or community feels comfortable knowing where the problem lies. But mental illness is just that -- an illness. The opposite of healthy, whole. And illnesses can improve or get worse. It's just that mental illness, more so than most other forms of disease, is especially impacted by the relationships and network one is in. So it's a lot easier for most people to conceive of a *person* as "mentally ill" as a euphemism for "f*cked up" than to use a term that implicates partners, families, and society. I'm not sure what that term would be, but sufferer is pretty accurate.