She's not crazy, she has Asperger's. This for sure is a more extreme representation of such, but good look at what it's like. The inability to pick up social cues, fixation on a specific topic or subject of interest, development of very specific daily routines.
I think it's important to clarify because there are some misunderstandings about Asperger's due in large part by people on the internet who "self-diagnose" themselves as such so they can use it as an excuse to be a jerk. They know they are being a jerk, they don't care. That's not what is being depicted here. The FMC is not doing anything with malicious intent, most of the time they are simply reacting to someone or something else.