I'm bi-polar (rapid cycling, type 2 apparently), and they sound bi-polar to me, could be wrong. Distancing themselves from you, and going out of the way to avoid you, and random acts of pointless verbal cruelty to friends and colleagues, it's nowt personal, it's just a perfectly normal (but extremely frigging annoying) and major factor in the condition/behaviour for many, but not all people who are bi-polar.
The age of the protagonists is an irrelevance, although the syndrome usually starts to show in the teens or early twenties, it is no real indicator of anything without a corresponding clinical diagnosis, which regularly may not actually be made until the patient is in their thirties or forties.
Because of the broad spectrum of symptoms/behaviour and ways of showing,in many situations, it is commonly misdiagnosed as simple depression or as a potentially contentious dis-associative disorder, then mistreated for years which just makes it worse,get them to a professional rather than a merely a gp who will just prescribe citolopram.
At the end of the day, the performance shows a quite a few bi-polar traits, but that doesn't mean she is, nothing more than an indicator really, sorry not to have been more help.