“The moment I laid eyes on her I knew she was somebody else, somebody I could love. And since somebody else never showed up, I did fall in love with her.” – Jarod Kintz  

Mental disorders affect many millions of people worldwide.  In some cases, the psychological problems experienced are exceedingly rare and/or bizarre.  In this final installment of the odd and unique I will be discussing the group of disorders known as delusional misidentification syndrome.

 A delusion is a fixed persistent false belief that is 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.  Delusional misidentification syndrome is the term used to describe a group of delusional disorders which can occur within the framework of a neurologic or psychiatric illness.  These delusional disorders all involve some sort of disturbance in the identification of a person, place or object, in that the sufferer holds on to the false belief that such has in some way changed or has been altered.

Delusional misidentification syndrome consists of many deviations including:

• Capgras syndrome
• Fregoli delusion
• Reduplicative paramnesia
• Intermetamorphosis
• Cotard’s syndrome

As presented a couple of weeks ago, 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belief that someone well known to them, typically a close relative or friend, or even their pets, has actually been replaced by an identical looking and behaving imposter.  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.

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The patient is absolutely convinced, even in the face of contrary evidence, that one or more people known to them have been replaced by an identical imposter.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.

Sufferers of Fregoli delusion believe that different people in their lives are actually the very same person, using an elaborate array of disguises and costumes to trick them.  Often this belief is of a paranoid nature with the delusional person believing that they are being persecuted by the person whom they believe to be following them.  The condition is named after the Italian actor Leopold Fregoli who was renowned for his ability to make quick changes of appearance during his stage act.  It was first reported 1927 by two psychiatrists who discussed the case study of a 27 year old woman who believed that she was being persecuted by two actors whom she often went to see at the theatre. She believed that these people “pursued her closely, taking the form of people she knows or meets.”

Reduplicative paramnesia is the steadfast belief that a place or location has been duplicated, simultaneously existing in two or more places, or that a place has been ‘relocated’ to another spot.  The term was first coined in the early 1900’s by the Czech neurologist, Arnold Pick.  He described a condition in one of his patients, believed to be suffering from Alzheimer’s disease, who was adamant that she had been moved from Dr. Pick’s city clinic to one she claimed was an ‘identical double’ in a familiar suburb.  To explain this incongruity she further claimed that Dr. Pick and his medical staff actually worked at both locations.

Sufferers of intermetamorphosis believe that familiar people in their environment have swapped identities, physically and psychologically, all the while preserving the same appearance.  While Fregoli delusion implies only a physical transformation, intermetamorphosis includes the transformation of the psyche as well.  As an example, the victim of intermetamorphosis may be deluded that their mother is actually their sister, and every time they see their mother, they see her as possessing both the physical and psychological characteristics of their sister.

Cotard’s syndrome, also known as Cotard’s delusion, is named after the French neurologist, Jules Cotard, who, in 1880, first described the condition of the person’s belief that they are missing body parts, internal organs, lost their blood or that they have somehow become emotionally “dead” and as such no longer actually exist.  They perceive themselves to be the “walking dead”.  It can, in even rarer of cases, also include delusions of immortality.   It is most often found in conjunction with psychotic disorders such as schizophrenia.

Although déjà vu is not technically considered part of delusional misidentification syndrome, it is itself often very bewildering.  You see or hear something and instantaneously have the sense that it is something you have experienced before.  Déjà vu is a French word with mean “already seen”.  It has other variants as well such as déjà senti (already thought), déjà vécu (already experienced), and déjà visité (already visited).  While déjà vu is somewhat common, and actually happens to the majority of people at least once in their life, some people actually experience persistent déjà vu.  They will swear that they “remember” things that, in reality, never happened.  So, for those suffering from unremitting déjà vu nothing to them feels new…as everything has already happened.