Ghouls live a life of misery - punctuated by passionate moments followed by intolerable anguish. Everything they do is under the scrutiny of their domitors, who may be loving one moment, and insanely cruel the next. They live in a perpetual identity crisis where part of them exists in the normal world and the other part exists in a world of blood, magic an intrigue. It is not surpising that many ghouls suffer the effects of psychosis.
This derangement causes the ghoul to suffer the effects of Frenzy in the same way vampires do. It is, in fact, the "short fuse" flaw for ghouls. It will incur a +3 diff on the standard frenzy chart for ghouls.
Severe Dysmenorrheic Psychosis
An amusing derangement only available to female ghouls. It is basically PMS for ghouls. If you want to get technical or the whole idea is just too silly for your tastes, you can alternately take Lunacy as a derangement, which would work in a similar way.
Self Defeating Personality Disorder
A type of masochism, this ghoul becomes very submissive. Domitors that are overbearing or abusive will find her ghoul welcoming the abuse, thriving on it even. A ghoul with this derangement must have a Masochist or Martyr nature.
Dependent Personality Disorder
A ghoul with this derangement has a major dependence on their domitor, to the point where the ghoul can no longer make day-to-day decisions. She will expect the domitor to tell her what to do, how to do it, and when to do it. Unlike Self-Defeating Personality disorder, the ghoul doesn't welcome abuse, but will take it out of fear of abandonment or fear of displeasing her master. This ghoul usually has a Sycophant nature.
Amnesia or Memory Lapses
This is a good derangement for a ghoul in denial. Many of the more pleasant aspects of her life can be conveniently shoved into the back recesses of her mind. Can be completely random, though this derangement can be potentially deadly if the domitor loses patience with his absentminded ghoul.
Obsessive Compulsive Disorder
This one is perfect for a ghoul that has a very exacting domitor. The ghoul becomes obsessed with certain routines, obsesses about pleasing her domitor and goes to ultimate lengths to make sure everything is in order. Perhaps she cleans the sink 20 times a day, because she knows her domitor insists on a spotless house. Perhaps she reorganizes her own closet repeatedly to make sure that her own life is in order, an outward reflection of her own chaotic life.
Narcissitic Personality Disorder or Megalomania
This one can be difficult to play, and another one that is potentially deadly. But imagine an older ghoul, he's empowered with disciplines, he's better and stronger than the other mortals he coverts with, and begins to feel that he is the center of the universe. Mostly works best for ghouls that tend to spend a lot of time in the mortal word, a ghoul that spends much of his time around vampires is likely to be repeatedly reminded of his inferiority.