What Is Capgras Syndrome?

Medically Reviewed by Smitha Bhandari, MD on March 11, 2024
4 min read

Capgras syndrome is a rare condition in which someone believes that their loved ones or others they know have been replaced with doubles or imposters. The belief is so real that nothing can correct this illusion.

Capgras syndrome, or Capgras delusion, is named for the doctor who treated a patient with it nearly 100 years ago. You may also hear it called imposter syndrome. But this condition is different from the more common “imposter syndrome” that you may have heard about.

Since Capgras syndrome is rare, it’s hard to study. Most of what we know comes from doctors’ reports of individual patients. (These are often called case reports.) Some research shows that it’s more common among people with neurodegenerative conditions like dementia: Up to 16% of those with Lewy body dementia or Alzheimer’s also have Capgras syndrome.

It’s also more likely in people with other brain conditions, such as Parkinson’s or epilepsy, in people who’ve had a stroke or a traumatic brain injury, or those with schizophrenia or bipolar disorder. One research estimate is that people with schizophrenia and dementia make up 81% of all cases.

One study about Capgras syndrome used a health database of 250,000 people in the U.K. It found just 84 cases in that large pool. One common thread was that many people with Capgras syndrome also had other types of delusions.

People with the condition also tended to be middle-aged, had other mental health issues in the past, and were twice as likely to be women.

There are two systems at work in your brain when you see a familiar face. The central nervous system scans the features of the face. The extended nervous system relays emotional information related to that face. Doctors still don’t know exactly how Capgras syndrome develops, but think a broken connection between those two systems prevents normal face recognition.

Many people with Capgras syndrome have one or more lesions, or areas of damage on the brain. These lesions don’t have to be on the exact parts of the brain responsible for recognition. They can simply be on areas connected to them.

There are many different risk factors for Capgras syndrome, including having dementia or Parkinson’s. Some people develop it after using large amounts of recreational drugs or alcohol. Others have had health issues like low thyroid, another metabolic condition, or a nutrient deficiency, like being short on vitamin B12.

The most striking symptom is the belief that the person’s loved ones are imposters. No amount of reasoning can change their mind.

Sometimes, the delusion is about more distant people, pets, or even objects. Delusions may come and go, especially among people with dementia. There may also be the symptoms of an underlying illness, like Alzheimer’s or a brain injury.

People used to think that Capgras syndrome made people violent, but experts now know this is rare and more likely to stem from another condition.

To make a diagnosis, doctors will do physical and mental health exams. They might order mental skills tests to check for dementia or other conditions, and brain imaging tests like MRI or EEG that look for lesions or other brain changes. Talking to family members or caregivers is important to learn when the delusions started and get other details.

The right treatment depends on the person’s situation. It may start with treating any physical or mental condition that could be causing Capgras syndrome. While the condition can be difficult to manage, proper treatment and good communication can lead to better outcomes.

Some dementia drugs, including donepezil (Aricept), galantamine (Razadyne), or rivastigmine (Exelon), may reduce symptoms. Antipsychotic medications such as aripiprazole (Abilify), olanzapine (Zyprexa), and pimozide (Orap) and may ease delusions and agitation. Antidepressants called SSRIs have helped in some cases.

Some experts suggest therapy first to help the patient, and their loved ones, to manage the illness. With habilitation therapy, loved ones try to put themselves in the patient’s place to better understand what they are feeling. Validation therapy gives the patient a sense of safety if they are scared that the imposter is there to hurt them. Family counseling might also help. Trying to persuade someone who has Capgras syndrome that they’re mistaken doesn’t work and can cause more distress for everyone.

Loved ones should always try to show compassion. Remember that the condition is causing the false belief. You might try to distract them with a favorite activity. A soothing voice and soft touch will show your support and help them deal with their reality.

Some experts refer to Capgras syndrome as imposter syndrome. This is different from the more common “imposter syndrome” that  refers to when someone doesn’t believe they’re as capable as they are.

Capgras syndrome may be called imposter syndrome because those with the condition believe that imposters have replaced their loved ones. This symptom of Capgras is an actual delusion, while the other imposter syndrome refers to an internal belief about oneself.