Multiple Personalities Support Group
Dissociative identity disorder is a diagnosis described as the existence in an individual of two or more distinct identities or personalities, each with its own pattern of perceiving and interacting with the environment. At least two of these personalities are considered to routinely take control of the individual's behavior, and there is also some associated memory loss,...
I am making big assumptions in that question, I know, but I assume she's got a really good reason to be that pissed off.
An idea to think about trying:
Get a movie in which a main girl character is narcissistic and naive, watch it at home, write down what comes up.
Please to not trash apartment while doing, though...but maybe you could get at why she's triggered and such that way in a controlled manner.