The closest fit seems to be intermittent explosive disorder, but I'm not sure it's quite right. The picture I've gotten from most credible-appearing websites (throwing out the ones peddling self-help books) is that people with this disorder appear normal between episodes. Particularly, this page struck me:
In DSM-III, and ever since, it was recognized that some individuals have bouts of explosive behavior that are NOT part of their underlying character structure, and, indeed, are experienced as ego-alien or ego-dystonic.Of course, the disorder also seems to be commonly misdiagnosed and no one agrees on just WHERE the lines should be drawn in diagnosing someone with it.
Anyway, my character seems to fit the disorder perfectly except for one thing: in her "normal" state, she still has an extremely bad temper. She just doesn't lose control and stab people most of the time--she just does typical bad temper things, like yelling and throwing things (she would stop before she hurt someone). As for remorse after an episode, the thing that bothers her most is that she lost control, not that she hurt someone--she's generally of the mindset of "I shouldn't have done it, but boy did they deserve it."
Do you think that intermittent explosive disorder still might fit, because there's a clear difference between her regular "temper" and her explosive episodes? Or does having "normal" problems with anger management count as a mental disorder that would preclude a diagnosis of IED?
The lack of remorse, by the way, doesn't at all point to antisocial personality disorder, since it's the ONLY symptom she has in common with it. What I've described is, I think, her only symptomatic trait. She's obsessive about being in control of herself and her things and her people, but I don't think that's part of a disorder ...
The reason why I ask is that this RPG requires the characters in her group to have a serious mental problem. It's best if she has an actual disorder, but if she doesn't, oh, well. I can turn it in anyway and they may or may not accept it.