The Cotard delusion, also known as nihilistic or negation delusion, is a rare neuropsychiatric disorder in which a person holds a delusional belief that he or she is dead, does not exist, is putrefying or has lost his/her blood or internal organs.Rarely, it can include delusions of immortality.It is named after Jules Cotard (1840–1889), a French neurologist who first described the condition,