Could be that, or could be some kind of neglect on the father's part, or maybe a bit of both... not sure how far 11 and 12 go into it, if at all. (I've glanced through them but not read them "properly" atm, and I haven't started work on 11 just yet.) FWIW I can't quote the exact characters right this second, but the Japanese seems to be the same sort of ambiguous phrase as saying "a difficult child" in English, i.e. if you Google it you get all kinds of stuff from websites suggesting serious psychological help to more general "Oh, don't worry, every child goes through a troublesome phase" reassurances. So you make a fair point, IMO, but it's hard to say.With her parents having problems reading and the grandma describing them as difficult children to raise, it makes me think they could also have some sort of disorder.