Trichotillomania: The Obsessive Need to Pull Out Scalp and Body Hair
Recently featured on the Tyra Banks show, this is a somewhat rare disorder in which the person afflicted feels an uncontrollable impulse to rip out their hair, any place they grow it, including eyebrows, eyelashes, and even pubic hair (ouch?).
Strangelove Syndrome: Hands Take a Path of Their Own
The sufferer's hands move without prompting, or being able to control it. This illness is particularly seen in patients with damage to the corpus collosum, the section in the brain that connects the right and left hemispheres. An interesting example of this was when a smoker used her un-affected hand to light a cigarette and place it in her mouth, but the "alien" hand pulled the cigarette out of her mouth and tossed it! It's in most cases like this, while strange and annoying, that Strangelove Syndrome does not cause the sufferer's hand to do any damage.
Diogenes Syndrome: Self-Neglect and Often Hoarding
This one is a sad disorder, because it can harm many living beings with just one person affected. Usually occurring in elderly people who are becoming senile, it is the lack of care for one's hygiene. The disease is often accompanied with an obsessive hoarding trait, in which the person will hoard objects, sometimes animals. Seen as animal cruelty by the general public, and easily defined as that as well, it is unintended cruelty. The person afflicted honestly believes that the animals are fine and don't want to part with them.
Cotard Delusion: The Belief of a Living Person that they are Dead
In a mild state, the sufferer hates themselves, and in the extreme they actually begin to deny their own existence. The brain area that recognizes faces and the section that controls emotion's connection to memory (the amygdala) are damaged. Therefore, the person can not see any familiarity in their face. Sufferers of this illness can have further delusions that their flesh is rotting or that they are being decomposed. They can refuse to eat, want to kill themselves, and are almost always severely depressed.
Arctic Hysteria: Cabin Fever of the Arctic
Defined as a cultural illness, the sufferer will display intense hysteria and insensitivity to cold, such as being naked in the snow (Wikipedia). One possible explanation is too much Vitamin A, which a diet of the Arctic supplies, especially through the organs of animals such as fish or the polar bear.
Apotemnophilia: The Desire to Have Limbs Amputated
Strangely enough, not only does the sufferer feel the need to amputate their limbs, they are sexually attracted to the idea and image. Some will damage a limb purposefully in order to get it amputated with reason, and others in more extreme cases will take the amputation into their own hands, literally.
