Anybody else wonder how Daisy came to even be there? *spoiler*

I think denial is powerful and at the time her family would have had her committed because of the OCD behavior she exhibits and the borderline bulimia behavior. It probably affected everything about her, and I get the feeling she probably cut herself prior to just when Lisa called her out on it... All are reasons to be institutionalized in the 60s.

The book says she was hospitalized seasonally, every Thanksgiving until just before Christmas. What's that about?

In the old days, accusing a man of rape or incest would get you committed, you could be deemed a nymphomaniac.