Psychosis is defined as being in a mental state of loss in reality. A huge amount of anger and feelings of being wronged could probably lead to a psycho ex-girlfriend. I'm just generalizing for fun that girls can be crazier in the head but not act out in it. Guys would be like get out of my way and going to kill you right now!
Trying to have Facebook discussions with an angry girl who isn't your friend and blocked your original account, she was definitely calling me psycho literally after reading every message. When I talked about what was making me mad, she called me a psycho. When I said that I want to get along with her, she called me a psycho. She was such an insecure punk and even tried to run to his fiancée to help me out. He was like OMG and then stopped responding after with some more cussing. I was going to deal with this sooner or later.
That's pretty much the big picture and the drama I had with her isn't even serious. It's up to me now how to pursue though because she totally stopped behaving that way with me on Facebook. I'm really happy with the parting messages I sent her so far. I was a work in progress and thankfully from having great relationships with female and hot buddies, I was able to close in with words that I wanted to convey and get the response that I wanted which was for her to finally stay quiet.