In the World of Darkness anyone can go mad, and given the horrible things that go on in the night, a lot of people see things and do things that cause their minds to reel. Sometimes, sanity simply breaks down and derangements are the result of a strain too great to bear. Other times, the mind bends in order to protect itself and has difficulty healing. But stress and genetics are not the only causes of mental illness. For some beings, madness is magically induced and forced upon them. It is whispered that some creatures embrace lunacy when they give themselves over to the service of the demonic - evil and chaos from beyond this world that corrupts anything it touches.
Derangements are not meant to completely and continually disable a character; if they do, chances are the player will have a deeply dissatisfying experience. In many cases, afflicted characters have periods of calm and normality. The trouble with derangements is that their symptoms keep coming back and they tend to show up at inconvenient times or in inconvenient ways. Some derangements, like delusions of grandeur, are ongoing problems with perception and thus are the status quo: most times, the character knows they're the best, but every now and then they find out they're not.
Derangements are meant to add variety and spice to the game, as well as horror and opportunities for advanced roleplaying, but they must be chosen very carefully. It is generally a bad idea for Storytellers to simply choose derangements for player characters without consulting the players. Some players might not feel that they are able to play a character with fits, or they might be very opposed to or bored by that idea. It must also be acknowledged that people come into contact with mental illness in real life and might be very disturbed by having to play a derangement that reminds them of something they've gone through, or something they've seen another suffer. Players and Storytellers should work together to choose derangements that will not throw the game into chaos or give all of the spotlight to one player, so that the entire group will have fun.
Below, I have compiled a list of derangements from as many books as I could. I have given the name of the derangement, the name of the book where it can be found, and the relevant page numbers. Some derangements, like paranoia, were printed in multiple books. When I have found a derangement in more than one place, I have noted it. For example, amnesia showed up in three places and is listed three times, each time with different book information. These derangements can be used for just about any character, whether Kindred or not, but some are specifically tailored for vampires or ghouls. Although a player can work with their Storyteller to make up a unique derangement, those listed in the books are there to help.
Although the books outline a lot of derangements, they by no means cover everything. Useful derangements can be found on other gaming web sites or on sites that discuss mental illness. Below are some other derangements that could easily apply to vampires.