Most of the film, I had it in one category (therefore one set of expectations). The final 6 minutes completely altered the purpose of the film and my interpretation.

The fits make for an extremely odd thread; [spoiler]by the end, you realize they are a red herring and don't belong at all![/spoiler] I don't know for sure, but my guess is that they are caused by [spoiler]self-induced traumatic brain injuries (at least among the older girls, before the younger girls begin to induce them through mass hysteria, which does happen in groups of people). The violent shaking of the head in their unique style of fight-dancing is bound to be bad for the brain tissue inside the skull.[/spoiler]

Nevertheless, this film is quite thought-provoking. While the fight-dancing (and boxing) throughout the film are an obvious metaphor, the fantasy ballet becomes very symbolic. The more one thinks about this film, the more understanding may be revealed, and that's great art's power of not spelling everything out! But the fits themselves and the mystery of their cause take away tremendously from the message [spoiler]as the lack of a solution/resolution[/spoiler] means viewers waste time on that rabbit trail when they should be wrestling with the message of the film.