This strange condition is pretty high up on the unbelievable scale. Cotards Syndrome/Cotards Delusion/Walking Corpse Syndrome more usually known as walking corpse syndrome is a condition where a person believes they are dead and they are walking the earth as a corpse. It’s a pretty rare mental illness that often manifests itself in individuals who have suffered some sort of serious brain damage. Persons plagued with this condition important believe that they do not exist- at least not in the physical sense. Some Individuals with this condition may believe that they may have lost an important body part such as a heart, liver or lung.
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 this Syndrome will frequently become inhibited 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 exceptionally distorted view of the world. This delusion is often found in psychotic patients suffering from schizophrenia. While Cotard's Syndrome doesn't involve hallucinations, the strong delusions are equivalent to those found in schizophrenic patients.
This distorted reality is caused by a malfunction in an area of the brain called the fusiform gyrus, which recognizes faces, and also in the amygdala, an almond-shaped set of neurons that processes your emotions. The combination is a lack of recognition when viewing familiar faces (even the face of the sufferer), leaving the person feeling disconnected with reality. [source: Scientific American]
A cure to Cotard’s Syndrome is currently unknown as scientists are still in uncharted territory when it comes to finding a treatment for the cause. Instead, focus lies primarily in treating the symptoms rather than the cause. Common treatments include anti-depressants and anti-psychotics, as well as the controversial electroconvulsive therapy.