Psychotic Episodes

[Segial]

I'm currently helping one of my players set up her character for the next dnd (3.5) session. She wants to play a dwarf and she took a liking of the derro race, but wants to play a good or neutral aligned character. So after looking into the derro race and finding out that they are murderous bat-**** crazy psychopaths, thats not an option. The idea is though that she could play someone of derro/dwarf decendants where the insanity would not be as dominant. I'm currently trying to figure out some combination of traits, flaws and/or feats that would represent that the character might enter psychotic episodes of delusions of grandeur, masochism, sadism, destructive rage or paranoia when stressed out. I'm not sure how to set this up properly that it is well-balanced and not too disruptive to the game. Any suggestions how to design something like that?

[Rubik]

There's the Willing Deformity: Insanity feat from the Book of Vile Darkness. Just take off the [Evil] descriptors and there you are. Her insanity takes the form of a psychotic episode whenever something hits her pre-approved list of "triggers" that you and she work together on. Make sure occurrances are reasonably rare, but not incredibly so. Each trigger has its associated action, which hits on a failed, scaling Will save (such as entering a rage as a barbarian of 1/2 her class level and physically attacking until the target of her insanity is dead, or entering a panicked state and fleeing/cowering whenever she notices that her trigger is within, say, 50 feet of her).

Could prove to be fun, so long as you hit her with dramatic irony. Just don't use it against her TOO often.

Alternatively, she's a rare sane derro. Maybe she was born in the plane of Limbo, or some canny psion Mind Seeded her.

[Synvallius]

You could try some sort of stimulus response chart, in which the player comes up with certain events that will prompt their insane dwarf character to act out if they fail a will save (not sure what DC you'd want for something like that, preferrably a relatively low DC so that they can generally maintain their composure, so something like 12 or 14 perhaps). If they fail the save they (or you, I suppose) would roll on a chart that would list some reactions (bursting out into maniacal laughter, bouts of uncontrollable weeping, unconciousness, etc.) and if they fail the DC by a significantly large number (by more than 5 or so) they would roll on another chart that has much worse reactions (randomly attacking allies, attacking themself, believing that they've turned into a duck, etc.). All that would be necessary for that would be for the player to write up a list of things that would set off their character, and you'd just have to set up two charts, each of which would only need ten or so insane responses. That's my idea, hopefully it's of some help.