Dr. Jules Cotard first described Cotard's syndrome in 1882 as the 'negation delirium' (le délire de négation). The term "walking corpse syndrome" has gained popularity. The syndrome is characterised by a series of delusory beliefs that the individual is dead or has lost his or her soul. Some people believe that the person is rotting on the inside or that he or she has lost organs, blood, or body parts. Cotard's syndrome is thought to be neurologically related to Capgras syndrome. Both syndromes are associated with brain damage that results in feelings of derealization (i.e., an altered experience or perception of the external world so that it seems unreal.)<