What is Capgras Syndrome?

Summary: Capgras syndrome is psychological condition that causes people to believe that an imposter has taken the place of someone they know well, such as a family member or friend.

Key Points:

• Capgras syndrome is classified as a delusional misidentification syndrome, which means a person develops the false belief that someone in their life has been doubled, or copied, and the person they see now is not the person they’ve always known.
• Capgras syndrome is associated with mental health disorders that include psychosis, as well as traumatic brain injuries, brain lesions, and various neurological conditions.
• Treatment for Capgras syndrome involves addressing the underlying cause, and in some cases, augmenting treatment for the underlying cause with psychotherapy and/or psychiatric medication.

Capgras Syndrome: Facts and Figures

The National Institutes of Health (NIH) define Capgras Syndrome as follows:

“Capgras syndrome (CS), or delusion of doubles, is a delusional misidentification syndrome. It is a syndrome characterized by a false belief that an identical duplicate has replaced someone significant to the patient. In CS, the imposter can also replace an inanimate object or an animal. It is widely regarded as the most prevalent of the delusional misidentification syndromes and appears in psychiatric and non-psychiatric cases, including patients with brain damage.”

In the general population, Capgras syndrome (CS) is rare. In psychiatric populations, evidence shows the following prevalence:

• All psychiatric patients: 1.3% – 2.5%
• Specific diagnoses:
  • Schizophreniform psychosis: 50%
  • Brief psychosis: 34.8%
  • Unspecified psychosis: 23.9%
  • Major depressive episodes: 15%
  • Delusional disorders: 11%
• Among patients with neurodegenerative disorders:
  • Alzheimer’s disease: 6%

Specific details on the prevalence of Capgras syndrome (CS) in patients with brain injuries are not available. However, experts identify the presence/development of CS in/after the following:

• Traumatic brain injury (TBI)
• Epilepsy
• Pituitary tumors
• Lewey body dementia
• Parkinson’s disease
• Cerebrovascular accident (CVA), a.k.a. stroke

Within clinical populations, i.e. people diagnosed with CS and delusional misidentification syndromes (DMS), data shows the following prevalence:

• Among people with CS:
  • 73% had schizophrenia
  • 26% had dementia
  • 17% had a mood disorder
• Among people with DMS:
  • 67% had CS

The data shows that although CS is rare in the general population, it is not uncommon in psychiatric populations. However, data on the prevalence of CS among people with brain injuries is scarce. That’s why the information on prevalence above – with regard to brain injury – contains only general information, rather than specific rates or percentages.

Capgras Syndrome: Symptoms and Causes

As we mention above, the primary symptom of CS is believing someone close to the individual – a family member, friend, and yes, a beloved pet – is an imposter or has been replaced by another person. People with CS:

• Truly believe their loved one or friend is not really their loved one or friend.
• Cannot be convinced otherwise with common logic, debate, or persuasion.

When interacting with the person they believe has been replaced or is an imposter, they may:

• Display agitation or anger
• Refuse to interact with them
• Refuse to believe any evidence that contradicts their delusion
• Threaten them
• Behave aggressively toward the person they believe is the imposter

Important Note

While evidence from a large scale review identifies a significant association between CS and aggression, the same review indicates that the “majority of case reports showed no propensity for violence.” In most cases, violence among people with CS is caused by another factor rather than CS itself.

Risk factors for aggression among people with CS include:

• Long duration of delusions
• History of violence of aggression
• Substance use/misuse
• Withdrawal from social situations
• Social isolation

We address aggression and violence in CS because among people who’ve heard of CS, that’s often one of the things they hear about. To be clear, evidence shows that violence is not an inherent aspect of CS, but rather, when it does occur, it’s caused by separate comorbidities and preexisting tendency toward violent outbursts, anger, or aggression.

Next, let’s look at the causes of and treatment for Capgras syndrome (CS).

What Causes Capgras Syndrome?

In some cases, CS is associated with the presence of a mental health disorder that includes symptoms of psychosis, or a degenerative neurological disorder, but CS can also develop after a serious brain injury.

The study “Delusional Misidentification Syndromes Following Acquired Brain Injury: A Scoping Review,” published in July 2026 offers insight into our current knowledge of CS and other delusional disorders associated with brain injury:

“Existing reports vary widely in phenomenological focus, terminology, and methodological quality, and no synthesis has yet systematically mapped the range of DMS presentations, etiologies, neuroanatomical bases, and outcomes following ABI. As a result, the prevalence, mechanisms, and clinical implications of post-ABI DMS remain poorly characterized.”

Due to this lack of scientific knowledge about CS after brain injury, the researchers reviewed 34 case reports on DMS – which includes CS – with the following goal:

“This review aimed to scope the available literature on the development of DMS following ABI.”

After a thorough review of the evidence, they found that injuries or lesions to specific brain areas were strongly associated with the development of CS. These brain areas include:

• Frontal lobe involvement in 78% of cases:
  • The frontal lobe is associated with reasoning, social cues, executive function (i.e. problem-solving and decision-making), learning, and memory.
• Temporal lobe involvement in 67% of cases:
  • The temporal lobe is associated with recognizing objects and faces, memory, language/expression, and processing emotions.
• Parietal lobe involvement in a small number of cases:
  • The parietal lobe is associated with perception of self, integrating sensory input, movement, and spatial awareness.

When we review those facts, it’s not difficult to understand how a syndrome like CS may develop. When the areas of the brain associated with facial recognition, social awareness, decision-making, memory, emotion, and integrating external input are damaged, it makes sense – even for someone who’s not an expert on neurobiology – that signals can get crosses, misinterpreted, and connected to emotion, resulting in the primary symptom of CS: misidentifying and developing mistaken beliefs about people or things.

Treatment for Capgras Syndrome

The primary treatment for CS involves treating the underlying cause of the syndrome, whether that cause is a mental health disorder with symptoms of psychosis, a neurodegenerative brain disease, or a traumatic brain injury.

Experts indicate that psychotherapy in combination with medication is the most common first-line treatment and is effective in most cases. Studies show:

• Establishing a positive treatment alliance between patient and provider is essential
• Establishing mutually agreed upon treatment goals improves outcomes
• Cognitive behavioral therapy (CBT) is recognized as an effective psychotherapeutic component of a multimodal treatment plan.
• Confrontation regarding misidentification is not effective

Medications that can improve symptoms include:

• Typical and atypical antipsychotics:
  • Risperidone, haloperidol, quetiapine, olanzapine, oxypertine
• Adjunct medications, including:
  • Selective serotonin reuptake inhibitors (SSRIs)
  • Serotonin antagonist and reuptake inhibitors (SARIs)
  • Benzodiazepines
  • Beta-blockers

When a person with CS displays aggression toward others or engages in self-harming behavior, a mental health provider may refer them for short-term emergency inpatient hospitalization for safety and stabilization.

The authors of the review we cite above indicate a wide variation in treatment outcomes, including:

• Full remission
• Partial remission
• Chronic, persistent symptoms

Here’s how they characterize those findings:

“Overall, outcomes highlight marked heterogeneity and a substantial risk of chronicity following ABI-associated Capgras syndrome.”

Experts on CS agree that the syndrome is unlikely to resolve on its own, and treating the underlying cause – sooner rather than later – improves overall outcomes. Therefore, if someone you know or love displays the symptoms we list above, the most important first step is to engage in professional support for all factors – injury, disease, mental health disorders – that may contribute to the development of Capgras syndrome.