The Cotard delusion (also Cotard's Syndrome and Walking Corpse Syndrome) is a rare mental illness, in which the afflicted person holds the delusion that he or she is dead, either figuratively or literally; yet said delusion of negation is not a symptom essential to the syndrome proper. Statistical analysis of a hundred-patient cohort indicates that the denial of self-existence is a symptom present in 69 percent of the cases of Cotard's syndrome; yet, paradoxically, 55 percent of the patients might present 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, and 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, of her need to eat, and said that she was condemned to eternal damnation, and so could not die a natural death. In the course of suffering "The Delirium of Negation," Mademoiselle X died of starvation.
As a mental illness, Cotard's Syndrome also includes the patient's delusion that he or she does not exist as a person; that he or she is putrefying; and the delusion either of having lost blood or internal organs, or both. The Cotard delusion is not included to the Diagnostic and Statistical Manual of Mental Disorders, neither to the DSM-IV (1994) nor to the DSM-IV-TR (2000) editions. In the tenth edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10), of the World Health Organization, code F22 identifies the Cotard delusion as a disease of human health.
The delusion of negation is the central symptom in Cotard's syndrome. The patient afflicted with this mental illness usually denies their existence, or the existence of a certain body part, or the existence of a portion of their body. Cotard's syndrome is in three stages: (i) Germination stage — the symptoms of psychotic depression and of hypochondria appear; (ii) Blooming stage — the full development of the syndrome and the delusions of negation; and (iii) Chronic stage — continued, severe delusions and chronic psychiatric depression.
The Cotard syndrome withdraws the afflicted person from other people, which includes neglecting his or her personal hygiene and physical health. The delusion of negation of the self prevents the patient from making sense of external reality, producing a distorted view of the external world. Such a delusion of negation usually is found in the psychotic patient who also presents schizophrenia. Although a diagnosis of Cotard's syndrome does not require the patient's having had hallucinations, the strong delusions of negation are comparable to the delusions found in schizophrenic patients.
The article Betwixt Life and Death: Case Studies of the Cotard Delusion (1996) describes a contemporary case of Cotard delusion, occurred in a Scotsman whose brain was damaged in a motorcycle accident:
[The patient's] 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 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 [his] mother's spirit to show [him] around hell", and that she was asleep in Scotland.
The article Recurrent Postictal Depression with Cotard delusion (2005) describes the case of a fourteen-year-old epileptic boy whose distorted perception of reality resulted from Cotard Syndrome. His mental-health history was of a boy expressing themes of death, of being sad all the time, of decreased physical activity in playtime, of social withdrawal, and of disturbed biological functions. About twice a year, the boy suffered episodes that lasted between three weeks and three months. In the course of each episode, he said that everyone and everything was dead, including trees; described himself as a dead body; and warned that the world would be destroyed within hours. Throughout the episode, the boy showed no response to pleasurable stimuli and had no interest in social activities.
The underlying neurophysiology and psychopathology of Cotard's Syndrome might be related to problems of delusional mis-identification. Neurologically, the Cotard delusion (negation of the Self) is thought to be related to the Capgras delusion (people replaced by impostors); each type of delusion is thought to result from neural misfiring in the fusiform face area of the brain (which recognizes faces) and in the amygdalae (which associate emotions to a recognized face).
The neural disconnection creates in the patient a sense that the face he or she is observing is not the face of the person to whom it belongs; therefore, that face lacks the familiarity (recognition) usually associated with it, which results in derealization — disconnection from the environment. If the observed face is that of a person known to the patient, he or she experiences that face as the face of an impostor (the Capgras delusion). If the patient sees his own or her own face, he or she might perceive no association between the face and his or her sense of Self — which results in the patient believing that he or she does not exist (the Cotard delusion).
Cotard's syndrome usually is encountered in people afflicted with a psychosis (e.g. schizophrenia), neurological illness, mental illness, clinical depression, derealization, and with migraine headache. The medical literature indicate that the occurrence of Cotard's delusion is associated with lesions in the parietal lobe. As such, the Cotard-delusion patient presents a greater incidence of brain atrophy — especially of the median frontal lobe — than do the people in the control groups.
The Cotard delusion also has resulted from a patient's adverse physiological response to a drug (e.g. aciclovir) and to its prodrug precursor (e.g. valaciclovir). The occurrence of Cotard delusion symptoms was associated with a high serum-concentration of 9-Carboxymethoxymethylguanine (CMMG), the principal metabolite of the drug aciclovir. As such, the patient with weak kidneys (impaired renal function) continued risking the occurrence of delusional symptoms, despite the reduction of the dose of aciclovir. Hemodialysis resolved the patient's delusions (of negating the Self) within hours of treatment, which suggests that the occurrence of Cotard-delusion symptoms might not always be cause for psychiatric hospitalization of the patient.
The article Cotard's syndrome: A Review (2010) reports successful pharmacological treatments (mono-therapeutic and multi-therapeutic) using antidepressant, antipsychotic, and mood stabilizing drugs; likewise, with the depressed patient, electroconvulsive therapy (ECT) is more effective than pharmacotherapy. Cotard syndrome resulting from an adverse drug reaction to valacyclovir is attributed to elevated serum concentration of one of valacyclovir's metabolites, 9-carboxymethoxymethylguanine (CMMG). Successful treatment warrants cessation of the drug, valacyclovir. Hemodialysis was associated with timely clearance of CMMG and resolution of symptoms.
In popular media
- In the episodes "Buffet Froid" and "Relevés" of TV series, Hannibal, a girl with Cotard's delusion was featured and was portrayed by Ellen Muth.
- In "Spark: A Novel," by John Twelve Hawks, the protagonist, an assassin, suffers from Cotard's delusion.
- In season one, episode ten of the TV series Black Box, "I Shall Be Released", a male patient thinks he's dead and is treated. 
- In The Mentalist: Season 3, Episode 3; "The Blood on His Hands" a "psychic" named Kristina Frye (played by Leslie Hope)is found after having been abducted by the serial killer Red John. When the series' title character, mentalist Patrick Jane (Simon Baker) and the CBI agents attempt to question her she will not answer and appears catatonic. Eventually Jane thinks of something that might work. He sits across from her and conducts a "seance" to summon her spirit. She smiles and says that she knew he would contact her. She is convinced that she is dead.
- In season four, episode 14 of the TV series Scrubs, a male patient thinks he's dead.
- Nac Mac Feegles from Discworld novels by Terry Pratchett, have a religious belief that they cannot be killed, because they are already dead.
- Berrios G.E. and Luque R. (1995) Cotard's delusion or syndrome?. Comprehensive Psychiatry 36: 218–223
- Berrios G.E. and Luque R. (1995) Cotard Syndrome: Clinical Analysis of 100 Cases. Acta Psychiatrica Scandinavica 91:185–188
- Cotard's syndrome at Who Named It?
- Berrios G.E. & Luque R. (1999) Cotard's 'On Hypochondriacal Delusions in a Severe form of Anxious Melancholia'. History of Psychiatry 10:269–278.
- Debruyne H., et al., "Cotard's syndrome: a review", Curr Psychiatry Rep. 2009 Jun;11(3):197–202; http://www.ncbi.nlm.nih.gov/pubmed/19470281
- Hans Debruyne, et al., "Cotard's Syndrome," Mind & Brain 2011; 2:(1). July 2011
- Yarnada, K.; Katsuragi, S.; Fujii, I. (13 November 2007). "A Case Study of Cotard's syndrome: Stages and Diagnosis". Acta Psychiatrica Scandinavica 100 (5): 396–398. doi:10.1111/j.1600-0447.1999.tb10884.x.
- Young, A.W., Robertson, I.H., Hellawell, D.J., de, P.K.W., & Pentland, B. (January 01, 1992). Cotard delusion after Brain Injury. Psychological Medicine, 22, 3, 799–804.
- Young, A.W.; Leafhead, K.M. (1996). Betwixt Life and Death: Case Studies of the Cotard Delusion (in P.W. Halligan & J.C. Marshall. (eds.) Method in Madness: Case studies in Cognitive Neuropsychiatry). Hove: Psychology Press. p. 155.
- Mendhekar, D. N., & Gupta, N. (January 01, 2005). Recurrent Postictal Depression with Cotard delusion. Indian Journal of Pediatrics, 72, 6, 529–31.
- Pearn, J.; Gardner-Thorpe, C (May 14, 2002). "Jules Cotard (1840–1889) His Life and the Unique Syndrome that bears his Name". Neurology (abstract) 58 (9): 1400–3. doi:10.1212/wnl.58.9.1400. PMID 12011289.
- Joseph, AB; O'Leary, DH (Oct 1986). "Brain Atrophy and Interhemispheric fissure Enlargement in Cotard's syndrome.". The Journal of Clinical Psychiatry 47 (10): 518–20. PMID 3759917.
- Anders Helldén, Ingegerd Odar-Cederlöf, Kajsa Larsson, Ingela Fehrman-Ekholm, Thomas Lindén (December 2007). "Death Delusion" (Journal Article). BMJ 335 (7633): 1305–1305. doi:10.1136/bmj.39408.393137.BE. PMC 2151143. PMID 18156240.
- Debruyne H., Portzky M., Van den Eynde F., Audenaert K. (June 2010). "Cotard's syndrome: A Review". Current Psychiatric Reports (review articledoi:10.1007/s11920-009-0031-z. PMID 19470281.) 11 (3): 197–202.