Cotard’s Syndrome

If you've ever felt dead tired, and/or you've said something like "God, I just wish I was dead!", this may be just the disorder for you.
Cotard's Syndrome is appropriately nicknamed "Walking Corpse Syndrome" because someone afflicted with it really seriously and truly believes that they are dead, they do not exist, or they've had all their blood or organs removed. Ya know, cause that just happens to all of us every day.
Cotard's is thought to be related to Capgras's Syndrome (a disorder in which the sufferer holds the honest belief that someone in their life has been replaced with an imposter or a duplicate of some sort) neurologically speaking, because both seem to signify a disconnect between the area of the brain that recognizes faces, and the area of the brain that is able to associate emotions with that very recognition (wow, men should really consider using this more often as an excuse for not recognizing a past One Night Stand). Because of this, someone suffering from Cotard's may not even recognize themselves when they look in the mirror and will begin to distance themselves emotionally, convincing themselves that they don't exist, or that they have died.
The syndrome is named after Jules Cotard (1840–1889), a French neurologist who first described the condition, which he called le délire de négation ("negation delirium"), in a lecture in Paris in 1880.He described the syndrome as having degrees of severity that range from mild to severe. Despair and self-loathing characterize a mild state. Severe state is characterized by intense delusions and chronic depression.
In this lecture, Cotard described a patient with the pseudonym of Mademoiselle X, who denied the existence of God, the Devil, several parts of her body, and her need to eat. Later she believed she was eternally damned and could no longer die a natural death. She later died of starvation.
Signs and symptoms
The central symptom in Cotard's syndrome is the delusion of negation. Those who suffer from this illness often deny that they exist or that a certain portion of their body exists. Cotard's syndrome has been found to have three distinct stages. In the first stage - Germination - patients exhibit psychotic depression and hypochondriacal symptoms. The second stage - Blooming - is characterized by the full blown development of the syndrome and the delusions of negation. The third stage - Chronic - is characterized by severe delusions and chronic depression.
People with the Cotard Delusion often become withdrawn from others and they tend to neglect their own hygiene and well-being. The delusion makes it impossible for patients to make sense of reality, which results in an extremely distorted view of the world. This delusion is often found in psychotic patients suffering from schizophrenia. While Cotard's Syndrome doesn't necessitate hallucinations, the strong delusions are comparable to those found in schizophrenic patients.
Distorted Reality
Young and Leafhead describe a modern-day case of Cotard delusion in a patient who suffered brain injury after a motorcycle accident:

The patient's symptoms occurred in the context of more general feelings of unreality and being dead. In January 1990, after his discharge from hospital in Edinburgh, his mother took him to South Africa. He was convinced that he had been taken to hell (which was confirmed by the heat), and that he had died of septicaemia (which had been a risk early in his recovery), or perhaps from AIDS (he had read a story in The Scotsman about someone with AIDS who died from septicaemia), or from an overdose of a yellow fever injection. He thought he had "borrowed my mother's spirit to show me round hell", and that she was asleep in Scotland.

An example of the distorted reality that results from Cotard Syndrome was described in a study of a 14-year-old patient with epilepsy. The child psychiatry OPD he was brought to described his history of expressing themes of death, being sad all the time, decreased play activity, social withdrawal, and disturbed biological function. He would have episodes about twice a year that lasted three weeks to three months at a time. In each episode, the child would say that everyone is dead, including trees. He would also describe himself as being a dead body. He warned that the world would be destroyed within a few hours. He showed no reaction to pleasurable stimuli and showed no interest in any activities.
Treatment
There are several reports of successful pharmacological treatment. Monotherapeutic and combination strategies are both reported.Antidepressants, antipsychotics and mood stabilisers are used. Many report positive effect with electroconvulsive therapy, mostly in combination with pharmacotherapy.