Cotard delusion


Cotard's delusion, also known as walking corpse syndrome or Cotard's 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 Cotard's 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, 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 and of her need to eat. She said that she was condemned to eternal damnation and therefore could not die a natural death. In the course of suffering "The Delirium of Negation", Mademoiselle X died of starvation.
Cotard's delusion is not mentioned in either the Diagnostic and Statistical Manual of Mental Disorders or the tenth edition of the International Statistical Classification of Diseases and Related Health Problems of the World Health Organization.

Signs and symptoms

Delusions of negation are the central symptom in Cotard's syndrome. The patient usually denies their own existence, the existence of a certain body part, or the existence of a portion of their body. Cotard's 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.
Cotard's syndrome withdraws the afflicted person 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 Cotard's syndrome does not require the patient's having 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 describes a contemporary case of Cotard's delusion which occurred in a Scotsman whose brain was damaged in a motorcycle accident:
The article Recurrent Postictal Depression with Cotard Delusion describes the case of a fourteen-year-old epileptic boy who experienced Cotard syndrome after seizures. His mental health history was of a boy expressing themes of death, chronic sadness, decreased physical activity in playtime, social withdrawal, and 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, 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.

Pathophysiology

The underlying neurophysiology and psychopathology of Cotard syndrome might be related to problems of delusional misidentification. Neurologically, Cotard's delusion is thought to be related to Capgras delusion ; 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 they are observing is not the face of the person to whom it belongs; therefore, that face lacks the familiarity normally associated with it. This results in derealization or a disconnection from the environment. If the observed face is that of a person known to the patient, they experience that face as the face of an impostor. If the patient sees their own face, they might perceive no association between the face and their own sense of self—which results in the patient believing that they do not exist.
Cotard's syndrome is usually encountered in people afflicted with psychosis, as in schizophrenia. It is also found in clinical depression, derealization, brain tumor, and migraine headaches. The medical literature indicate that the occurrence of Cotard's delusion is associated with lesions in the parietal lobe. As such, the Cotard's delusion patient presents a greater incidence of brain atrophy—especially of the median frontal lobe—than do people in control groups.
Cotard's delusion also has resulted from a patient's adverse physiological response to a drug and to its prodrug precursor. The occurrence of Cotard's delusion symptoms was associated with a high serum-concentration of 9-carboxymethoxymethylguanine, the principal metabolite of acyclovir.
As such, the patient with weak kidneys continued risking the occurrence of delusional symptoms despite the reduction of the dose of acyclovir. Hemodialysis resolved the patient's delusions within hours of treatment, which suggests that the occurrence of Cotard's delusion symptoms might not always be cause for psychiatric hospitalization of the patient.

Diagnosis

According to the DSM-5, Cotard's delusion falls under the category of somatic delusions, those that involve bodily functions or sensations.
There are no further diagnostic criteria for Cotard's syndrome within the DSM-5, and identification of the syndrome relies heavily on clinical interpretation.
Cotard's delusion should not be confused with delusional disorders as defined by the DSM-5, which involve a different spectrum of symptoms that are less severe and have lesser detrimental effect on functioning.

Treatment

treatments, both mono-therapeutic and multi-therapeutic, using antidepressants, antipsychotics, and mood stabilizers have been successful. Likewise, with the depressed patient, electroconvulsive therapy is more effective than pharmacotherapy.
Cotard's syndrome resulting from an adverse drug reaction to valacyclovir is attributed to elevated serum concentration of one of valacyclovir's metabolites, 9-carboxymethoxymethylguanine. Successful treatment warrants cessation of valacyclovir. Hemodialysis was associated with timely clearance of CMMG and resolution of symptoms.

Case studies