Schizophrenia
Conflicting, unresolveable sets of feelings and impulses can cause a victim to develop schizophrenia, which manifests as a withdrawal from reality, violent changes in behavior, and hallucinations. This is the classical sort of derangement, causing victims to talk to walls, imagine themselves to be the King of Siam, or receive instructions from their pets telling them to murder people.
Roleplaying this derangement requires careful thought, because the player must determine a general set of behaviors relevant to the trauma that caused the derangement. The hallucinations, bizarre behavior and unseen voices stem from a terrible inner conflict that the individual cannot resolve. The player needs to establish a firm idea of what that conflict is and then rationalize what kind of behavior this conflict will cause.
Kindred with this derangement are unpredictable and dangerous. In situations that trigger a vampire's inner conflict, the difficulties of all rolls to resist frenzy increase by three, and the vampire loses three dice from all Willpower rolls.
