Nowadays this would be a different film.
Or even just a few decades later. Taken at face value, the reason behind a shy, withdrawn, neurotic girl who attempts suicide, refuses to talk about it, has trouble accepting love from her partner, has been brought up alone by a controlling distant relation who hates women and prevents her from playing music that she likes or having boyfriends, tries to hit her when angry and breaks things when questioned by a psychiatrist: nowadays an audience doesn't think, "Aha- her problem is repressed love and sexual tension between her and her guardian". Nowadays there'd be a likelier, uglier reason.
Don't get me wrong- I enjoy this film in the spirit intended, as a piece of stylish gothic melodrama with great performances and entertaining panache, and I'm not intent on dismissing it in any way, but every now and then I like to imagine how books and films would have been tackled in different eras.