“The lesson of Capgras syndrome is that even our “normal” reality may be little more than a delusion.” – Thomas Grüter and Ulrich Kraft

Mental disorders affect many millions of people worldwide.  In some cases, the psychological problems experienced are exceedingly rare and/or bizarre.  Continuing with the series of the somewhat unique, today’s column is about the fascinating, and confusing, disorder known as Capgras syndrome.

Capgras syndrome, also known as Capgras delusion, is named for the French psychiatrist Jean Marie Joseph Capgras who first described the syndrome along with his colleague Jean Reboul-Lachaux, is a rare disorder in which the person has a persistent delusional belief that someone well known to them, typically a close relative or friend, or even their pets, has actually been replaced by an identical looking and behaving imposter.  It is technically classified as a delusional misidentification syndrome, which is a class of disorders involving the misidentification of people, places, or objects.  The sufferer of Capgras syndrome may actually see them self as their own double.

People affected by Capgras syndrome are able to distinguish faces and have a sense that they look familiar, but they are unable to link that particular face with the feeling of familiarity that should be present.  It is actually a dilemma of disconnection.  The knowledge of familiarity is there, but not the emotional sense that should be connected to it.  Delusions are defined as fixed persistent false beliefs that are held with extreme certainty even in the face of significant evidence to the contrary. In contrast, hallucinations are perceptions that have no basis in reality.  Individuals tormented by Capgras syndrome, because of the associated delusion(s), often believe they are living in a world of impersonators.  This can create such psychological disequilibrium that it may ultimately lead to psychotic behavior.  Capgras syndrome, and the paranoia often created by the psychological disruption it can create, has formed the foundation of some mainstream films such as Invasion of the Body Snatchers, The Stepford Wives, and Total Recall.

Capgras syndrome typically has the following features:

• The patient is absolutely convinced, even in the face of contrary evidence, that one or more people known to them have been replaced by an identical imposter.
• The patient is actually aware that these perceptions are abnormal.
• The misperceptions can include familiar pets and objects.
• There are no hallucinations.
• The “imposter” is typically a close person in the patient’s life.

Although considered quite rare, Capgras syndrome is more commonly found in patients suffering from schizophrenia, brain injury, dementia, and neurodegenerative diseases.  It has also been found to be more often found in certain other disorders such as migraine headache, hypothyroidism, and diabetes.  It is more common in woman than men, and tends to occur more often in the elderly.

Although there remains some controversy as to its actual cause, organic factors versus psychodynamic factors, at this point in time the vast majority of investigators now believe that Capgras syndrome is caused by some sort of  organic brain problem as many patients are found to have signs of head trauma, or other organic conditions such as Alzheimer’s or epilepsy.  One theory is that somewhere along the neuronal pathways the brain is not communicating normally between certain of its parts the way it should.  This problem in “communication” may be occurring between the facial recognition visual processing center and emotional response center (limbic system) of the brain.  Another hypothesis is that the problem is one of memory.  Vilayanur Ramachandran, a neuroscientist and Professor in the Department of Psychology and the Neurosciences Graduate Program at the University of California – San Diego, and William Hirstein, the current chair of the Philosophy Department at Elmhurst College, put forward the hypothesis that the syndrome is caused by a glitch in “memory management.”  The example they site in trying to explain the problem is to think of the brain as a computer. Each time you create a new document you then save and close it in a new file.  When you wish to retrieve the information you open the old file, work with it, add to it, and then once again save and close it.  Ramachandran and Hirstein postulate that people with Capgras syndrome may keep creating new files instead of accessing the existing one, so that when you leave, and then return, you have become a new person.  A person that looks like the one who left, but just slightly different enough as to be someone else.

Interestingly, there have been studies in which blind people experience Capgras syndrome whereby their delusion is of the voice of a person, believing that the voice is that of an imposter.  Other studies have demonstrated that some sufferers convinced by looking at a friend or family member that they were an imposter, yet were able to easily recognize their voice over the phone.

Treatment of Capgras syndrome typically includes a combination of individual psychotherapy and psychiatric medication.   Cognitive Behavioral Therapy (CBT) techniques that include reframing and reality testing can be helpful in treating the delusions by helping the patient surmount the challenge they have believing the “substitution” is real.   Furthermore, the use of selective serotonin re-uptake inhibitors (SSRI) and/or antipsychotic medication can also improve the patient’s mood and thought disorder.

Next week I will continue the series on the rare and bizarre when I present the traveling disorders known as Voyager syndrome.