That is a tough one and I'm very sorry to hear that you and your family have to go through this. I have a similar situation with our oldest daughter as far as turning the family upside down, she does what you describe to us too. She isn't suicidal at least though. I believe you made the right decision not to subject you marriage and family to that. I'm sorry I can't be of much if any help as far as the suicidal part goes except maybe the mental institution is what she needs right now. I know thats a hard thing to do but maybe in such a structured enviornment she can get the help she need and preserve her life at the same time while she gets the help.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!