What Is Capgras Syndrome?

Capgras syndrome (CS) could have you, as a caregiver or care partner, trying to convince a loved one that you are not an imposter.

Capgras syndrome is a psychological disorder that can cause someone to believe that someone they love, a person close to them, has been replaced by an imposter, a duplicate.¹

It can contribute to an already complicated quality of life for people with dementia and their caregivers.²

What is it?

A type of delusional misidentification syndrome (DMS), Capgras syndrome results from a disturbance in the brain’s facial recognition system and can be associated with brain lesions.³

The theory is that a person develops delusions, creating the thought that a friend, spouse, parent, or other close family member has been replaced by an identical-looking impostor.

How common is it?

Delusional misidentification syndromes (DMS) are relatively uncommon.² Capgras is associated with neurodegenerative disorders like Parkinson’s disease (PD), and in particular with Lewy body dementia (LBD).

It is the most common type of dementia after Alzheimer’s disease and is characterized by the development of an abnormal buildup of proteins in the brain called “Lewy bodies”. Psychosis occurs in 40% of people with PD. Those with advanced disease can manifest delusions and other psychotic symptoms.

People tend to experience a more significant emotional response seeing the faces of people they love. Thus they experience loved ones as impostors in person but generally not over the phone. This has led to the conclusion that the phenomenon had a strong visual component.¹

Who gets it?

CS affects between 16 and 28% of people with Lewy body dementia, around 15% of those with Alzheimer's, and is present but less common in people with basic Parkinson’s. Those with anxiety have a 10x risk of developing Capgras syndrome.¹

Deep brain stimulation (DBS) does not appear to be directly correlated to CS but there are some reports of PD patients with a history of DBS that developed this type of delusion.²

Thus those with advanced PD who undergo DBS should be regularly screened for symptoms of psychosis and consideration that CS is a possibility.⁵

Why does it develop?

The pathophysiology of Capgras is not clear. Cognitive scientist Max Coltheart and his colleagues describe a two-factor theory of delusional belief that has been confirmed by brain imaging.

The first is a form of brain damage that prevents familiar faces from evoking an emotional response. The second prevents the ability to reject the delusional belief.¹

There is a disconnect in the pathway between the temporal lobe, the area of the brain responsible for facial processing, and the limbic circuits associated with appropriate personal and emotional responses.

How is it treated?

The first step in treating CS is to determine if there is any underlying illness.¹ Medical conditions such as urinary tract infections or REM sleep disorders can trigger delirium and delusions.

If Capgras syndrome is recognized early, pharmacological intervention may help alleviate symptoms. Typical antipsychotic medications may not be appropriate as they can worsen PD symptoms, or cause other potentially fatal complications. Two drugs commonly used are quetiapine and clozapine because of the limited side effects.⁴

Tips to help loved ones

Because of the disconnect between the person and their loved ones, there is a significant risk of violence against the person who is misidentified as an intruder.¹

The risk has been shown to increase in male patients, in those who have had delusions for an extended time, and in patients with concomitant paranoia or substance abuse.

Some tips for helping patients and families cope include communication techniques, medications, and creative problem-solving that can be useful in caring for a person with CS.

It is important to validate their feelings and concerns, reassuring them they are safe. Take the time to evaluate whether it is better to visit during certain times of the day, alone or with others.³

Rely on auditory interactions. Since it is difficult or impossible for people to visually connect with loved ones, sound is an alternative way to communicate.

If face-to-face encounters cause stress, try a telephone conversation. Another technique is to announce yourself while still out of sight. This helps to establish an emotional connection and begin an interaction as you come into view.

Finally, caregivers need to remember to take care of themselves first; take time away, recognize limitations and rely on other support systems including friends, family, and community and healthcare resources.