Cotard delusion, or Cotard’s syndrome, or “walking corpse syndrome,” occurs when a person believes they are dead, do not exist, have missing body parts, or body parts that are disappearing. It is a rare and serious syndrome that can signify schizophrenia or other conditions.

It is not always the case that a person with Cotard’s syndrome has schizophrenia. Many conditions can cause Cotard’s syndrome, and some people experience it as a short-lived symptom following a seizure.

Some scientists believe that Cotard’s syndrome may have links to lesions in the nondominant hemisphere of the brain. This is the side of the brain that is on the same side of the body as a person’s dominant hand. However, a range of factors may influence its development.

This article looks more closely at Cotard’s syndrome and schizophrenia, including their relationship, signs and symptoms, and treatment.

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Cotard delusion, or Cotard’s syndrome, is a rare and severe change in a person’s perception of their body or existence. It encompasses a group of false but strong beliefs that can vary in nature.

For example, some people with this syndrome might believe they are dead, while others may think they are immortal.

Delusions are different from beliefs that are unusual or misguided. A person with Cotard’s syndrome feels adamant that their perceptions are true, even when the evidence says otherwise.

This may cause them to exhibit behaviors they otherwise would not. For example, a person who believes they are dead may stop eating.

Other names for Cotard’s syndrome include “walking corpse syndrome” or nihilistic delusion.

Learn about delusion disorder here.

The main symptom of Cotard’s syndrome is a false belief about a person’s existence. They may believe that:

  • they do not exist
  • they are dying or dead
  • some of their body parts are missing
  • they are immortal, or that they have died and begun a new life

People with this syndrome can also believe their organs are falling apart, disappearing, or being eaten.

A 2017 review found that 8 out of the 12 people identified as having Cotard’s syndrome felt they had died. Of these, three believed health professionals had killed them. Four reported that they were in the process of dying.

Learn more about the types of schizophrenia here.

Yes, Cotard’s delusion can be a symptom of schizophrenia. However, it is rare. A 2021 paper reports that less than 1% of people with schizophrenia have it. A person does not need to have this syndrome to receive a schizophrenia diagnosis.

Schizophrenia is a recognized cause of Cotard’s syndrome. The small 2017 review of 12 people with Cotard’s syndrome found that two also had schizophrenia.

People with schizophrenia, bipolar disorder, and other mental health conditions can experience one or types of delusions, including:

  • delusions of grandeur, which is the belief that a person is powerful, special, or a more important being than others.
  • persecutory delusions, which is when a person incorrectly believes someone or something is trying to harm them
  • delusions of misidentification, which is the false belief that two people or places have switched around
  • religious delusions, which is when a person believes they are a god or a god-like entity
  • erotomanic delusions, which is when a person believes that someone, such as a celebrity, is in love with them

Learn more about the myths and truths about schizophrenia here.

Researchers do not fully understand what causes Cotard’s syndrome or why it can occur in those with schizophrenia.

Cotard’s syndrome is a rare diagnosis and most people with conditions that can cause it never develop it. This may mean a combination of biological, psychological, social, and environmental factors play a role.

Researchers have found that people with Cotard’s syndrome tend to have changes in their brains, suggesting that underlying neurological issues may play a role in its development. For example, the 2018 paper reporting on 12 people with Cotard’s syndrome found that:

  • four people had changes to the frontal lobe of the brain
  • four had a generalized loss in brain volume
  • five showed signs of decreased blood flow in some areas of the brain
  • seven had lesions on at least one side of the brain

Eight of the participants had a history of psychiatric diagnoses, such as schizophrenia, depression, or substance misuse. Five also had neurological symptoms.

Some of the conditions that may increase the risk of Cotard’s syndrome include:

  • Epilepsy: A person may experience delusions because of epilepsy-related brain damage or in the post-seizure period.
  • Neurological diseases: Conditions that cause damage to the brain, such as dementia, stroke, and traumatic brain injury (TBI), may cause delusions.
  • Substance misuse: A person may develop delusions while under the influence of drugs or due to drug-related brain damage.
  • Psychiatric conditions: Mental health disorders such as depression often occur in people with Cotard’s syndrome.
  • Infections: Infections, especially in the brain, may cause delusions and other neurological symptoms.

Learn about the link between depression and substance misuse here.

Doctors can typically identify Cotard’s syndrome by talking with a person about how they feel. However, because this syndrome is a symptom of an underlying illness, they will also need to identify the cause.

If a doctor suspects a person may have schizophrenia, they may recommend a psychiatric assessment. This involves answering a series of questions that inform a mental health specialist about a person’s mental state.

To receive a schizophrenia diagnosis, a person has to meet certain criteria. The Diagnostic and Statistical Manual of Mental Disorders (DSM-V) states that a person may have schizophrenia if they have two or more of the following symptoms for a significant length of time in 1 month:

At least one of the symptoms must be delusions, hallucinations, or disorganized speech, and they must significantly adversely impact a person’s ability to function in various aspects of life.

If the cause is not schizophrenia, doctors may recommend:

  • blood tests to look for infections
  • brain imaging scans to look for damage in the brain
  • drug testing

Learn more about hallucinations here.

Because various conditions can cause Cotard’s delusion, there is no single treatment that will treat all cases. Instead, doctors treat the underlying cause. Depending on what the underlying cause is, treatment may involve:

Another potential treatment is electroconvulsive therapy (ECT), which delivers an electrical shock to the brain. This can alter neurotransmitters and brain function, which may improve symptoms for some.

Learn more about ECT, including its benefits and risks.

A person should seek medical care if they believe they are dead, dying, or that a part of their body is missing, as this could signify a delusion.

If a loved one displays signs of delusions, offer support and compassion. Do not try to argue or persuade them they are wrong, as this will not change their mind. Instead, suggest they seek medical care and offer to go with them.

Some people with Cotard’s delusion may believe they do not have to care for themselves anymore.

A person needs emergency care if they engage in behavior that may hurt themselves or others, such as:

  • jumping from buildings or bridges
  • not eating or drinking
  • threatening to self-harm
  • violence or aggression

If any of the above occur, dial 911 or the number of the nearest emergency department.

Cotard delusion, or Cotard’s syndrome, is when a person believes they are dead, dying, or immortal. They may also believe parts of their body are missing or are disappearing. For example, they may think a virus is destroying their organs.

Cotard’s syndrome is rare, including among people with schizophrenia. However, of those with the syndrome, schizophrenia is one of the potential causes. People with schizophrenia can have several different types of delusions.

Other potential causes of Cotard’s syndrome include neurological conditions, such as epilepsy, drug misuse, dementia, and brain infections. As a result, it is vital people with this syndrome seek treatment so that a doctor can identify and treat the cause.

Learn more about mental health conditions in our dedicated hub.