Cotards syndrome exists in three stages:

Germination stage: symptoms of psychotic depression and of hypochondria appear;
Blooming stage: full development of the syndrome and delusions of negation; and;
Chronic stage: continued severe delusions along with chronic psychiatric depression.Cotards syndrome withdraws the person with the condition from other people due to neglect of their personal hygiene and physical health. Delusions of negation of self prevent the patient from making sense of external reality, which then produces a distorted view of the external world. Such delusions of negation are usually found in schizophrenia. Although a diagnosis of Cotards syndrome does not require the patient to have had hallucinations, the strong delusions of negation are comparable to those found in schizophrenic patients. Distorted reality
The article Betwixt Life and Death: Case Studies of the Cotard Delusion (1996) describes a contemporary case of Cotards delusion which occurred in a Scotsman whose brain was damaged in a motorcycle accident:

[The patients] symptoms occurred in the context of more general feelings of unreality and [of] 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 sepsis (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 sepsis), or from an overdose of a yellow fever injection.
Cotards delusion, also known as walking corpse syndrome or Cotards syndrome, is a rare mental disorder in which the affected person holds the delusional belief that they are dead, do not exist, are putrefying, or have lost their blood or internal organs. Statistical analysis of a hundred-patient cohort indicated that denial of self-existence is present in 45% of the cases of Cotards syndrome; the other 55% of the patients presented with delusions of immortality.In 1880, the neurologist Jules Cotard described the condition as le délire des négations ("the delirium of negation"), a psychiatric syndrome of varied severity. A mild case is characterized by despair and self-loathing, while a severe case is characterized by intense delusions of negation, and chronic psychiatric depression.The case of "Mademoiselle X" describes a woman who denied the existence of parts of her body (somatoparaphrenia) and of her need to eat. She claimed that she was condemned to eternal damnation, and therefore could not die a natural death. In the course of experiencing "the delirium of negation", Mademoiselle X died of starvation.Cotards delusion is not mentioned in either the Diagnostic and Statistical Manual of Mental Disorders (DSM) or the 10th edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) of the World Health Organization. Signs and symptoms
Delusions of negation are the central symptom in Cotards syndrome. The patient usually denies their own existence, the existence of a certain body part, or the existence of a portion of their body.