Self-Annihilation Impulse
This derangement is more common among older vampires, although there's nothing stopping a neonate from acquiring the affliction. the afflicted vampire feels a deep sense of revulsion for his flesh, and is literally terrified of the thought of "living" forever, or of continuing to exist inside a cold, dead shell. This revulsion is entirely unconscious, however; on a conscious level, the vampire is wholly unaware of his "death wish," although he may demonstrate a morbid streak.
Whenever the character is confronted with more-or-less direct evidence of his immortality - such as visiting the churchyard where his mortal daughter is buried, or watching a ghoul die - he must make an immediate Willpower roll, or begin to undertake some sort of potentially deadly behavior. This behavior might be as direct as storming into Elysium and giving the prince a piece of his mind, or it might be more subtle, such as breaching the masquerade by talking to a reporter.
In any event, the pursuit of self-destruction is not a conscious decision, and it's not open for debate. The character will doggedly go about his "chosen" task until it's completed, resisting any attempts to talk him out of it. He may even consciously believe that the actions he's undertaking are perfectly safe. The compulsive behavior lasts only fora scene or so; however, depending on the nature of the threats he's called down on himself, the consequences can last quite a bit longer.