I've always wondered this. When I was younger, I was always wondering, why me?? But since mental illness is one of those things that is taboo for come cultures and some families, I'm not sure. Since my parents split when I was young, I don't really know my dad's side too well to say anything. And as far as I know on my mom's side of the family, I am unaware of any mental illnesses on that side either. But I did find out not too long ago that my grandmother's younger brother was "sent away" for some reason. But it was never discussed. Since this was back in the 1920-1930ish era, no one talked about it. At any rate, I can say my mom has some depression issues and my dad has some substance abuse issues, and that's all I can confirm from just being their daughter.