Delusional Misidentification and Reduplicative Phenomena: an Introduction
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The proper APA Style reference for this manuscript is:
MARTIN, C. L. (2002). Delusional Misidentification and Reduplicative Phenomena: an Introduction. National Undergraduate Research Clearinghouse, 5. Available online at Retrieved April 25, 2017 .

Delusional Misidentification and Reduplicative Phenomena: an Introduction

Sponsored by: GARY FISK (
Delusional Misidentification Syndromes and Reduplicative phenomena, including Cotardís delusion, Fregoliís delusion, and the more familiar Capgras delusion, are explored from an introductory standpoint. These bizarre and fascinating conditions are demystified with a simple review of pertinent literature. The research indicates that this strange symptomatology can be reasonably explained by referring to specific loci of damage in the brain. Though delusional misidentification and reduplicative phenomena are rare, they do provide insight into several facets of neuroanatomy and biopsychology.

The field of neuroscience may lay claim to some of the most bizarre conditions of medicine and psychology alike. From Aspergerís syndrome to Wernickeís aphasia, there is certainly no shortage of the strange and surreal in neuropsychology; mere mention of the alien hand phenomenon may elicit raised eyebrows and hearty skepticism. Within the realm of delusional misidentification and reduplicative phenomena, disorders range from the mildly peculiar, as in temporal reduplication or a prolonged dťjŗ vu, to the flat-out fantastic, as in Cotardís delusion, a personís belief that they (themselves) are dead (Weinstein, 1996). These delusions of reduplication require neuroscientists to engage in a level of sleuthing that would likely impress even Sherlock Holmes. Though characterized by unique and bizarre symptomatology, delusional misidentification may be a logical manifestation of damage to specific areas of the brain.Among cases of delusional misidentification, many are caused by known physiological etiologies (Breen, Caine, Coltheart, Hendy, & Roberts, 2000; Luzatti & Verga; 1996; Ramachandran & Blakeslee, 1998; Weinstein, 1996). Focusing on the neurological bases, these delusions can result from traumatic brain injury, brain tumor, aneurysm, stroke, epilepsy, Alzheimerís disease, and other brain lesions (Weinstein, 1996). Most often it is damage to the right cerebral hemisphere, as demonstrated by brain imaging and neuropsychological testing, that leads to misidentification syndromes; although, bilateral pathology has also been implicated (Breen, et al., 2000; Pisani, Marra, & Silveri, 2000; Young, 2000). Because cracking the mysteries of reduplicative phenomena in the biological sense is a relatively new endeavor, the theories are rapidly evolving, undergoing constant revision and refinement. For this reason, it is hard to pinpoint one widely accepted theory of misidentification; however, recent works by Young, Ramachandran, and others have given creative and plausible insight into the neurological origins of delusional misidentification and reduplicative phenomena (Ramachandran & Blakeslee, 1998; Young, 2000). So what is delusional misidentification exactly? The answers arenít perfectly clear, but the names may be good place to start. Reduplicative misidentification syndrome, delusional misidentification syndrome, and reduplicative phenomena are all phrases used to describe certain delusions of times, places, objects, persons, including the Ďselfí, and even body parts (Weinstein, 1996). As an example, an affected person might believe that an imposter has replaced his or her spouse. The delusional aspect of these disorders is clear. The emphasis on reduplication, however, is a little murkier. It is referred to as reduplication evidently because the focus of the delusions can be duplicated more than once. That is, there can be more than one imposter, double, or copy (Weinstein, 1996). This is probably a blanket term, though, because in some cases, there is no duplication at all, but more of a transformation. For example, a person with the delusional misidentification syndrome of interemetamorphosis believes that someone has physically changed into someone else, without duplication. There may be a fine line (if any line at all) between the technical differences of these delusions. Additionally, there seems to be no cohesive agreement among researchers with regard to respective definitions or discrete categories; therefore, they are often referred to collectively (Weinstein, 1996; Young, 2000). Reduplicative phenomena contribute to a wide range of symptomatology, and though the different syndromes may occur on a continuum, each has itís own unique manifestations.

Patients with the Capgras delusion believe that some people are imposters. After a car accident, a patient named Arthur, was convinced that his parents were imposters, that is, they were not his real parents. As is often the case, the delusion involves only certain people, usually those who are emotionally closest to the patient. In many instances, the person with a misidentification delusion has no animosity toward the purported imposters. Indeed, Arthur, though bewildered at why people would pretend to be his parents, seemed thankful for their care and kindness (Ramachandran & Blakeslee, 1998). Unfortunately, this isnít always the case, as there are several reports of violence and aggression associated with misidentification delusions. One particularly macabre illustration involves decapitation of a man believed to be a robot. The delusional individual cut off the manís head to look for electronic evidence of his theory (Young, 2000).

Fregoliís delusion is characterized by a belief that someone, often someone considered threatening by the patient, is disguised as another person. One patient, Betty, believed that a former lover and his girlfriend were monitoring her. She was convinced that they were occupying neighboring homes and garages, rapidly changing their identities, all in an attempt to prevent her from telling family and friends about her previous affair with the gentleman. Betty thought that these people were stunning masters of disguise, that they could change their facial appearance, clothes, and even their sex at a momentís notice (Ellis & Szulecka, 1996).

Reduplicative paramnesia is the delusion that there exists identical places or events. In one such case, a woman who had sustained a head injury in a purse snatching incident, believed that she had actually be victimized twice, by the same man (Pisani, Marra, & Silveri, 2000). In another example, patient DB, whose husband had died some years earlier, thought her spouse was staying in the same hospital as she. It is interesting that in this case as well as many others of delusional misidentification, patients can actually be very logical, have an otherwise firm grasp on reality, and be well aware that the notions of their delusions are absurd. They know the impossibility of their claims, yet rarely can they be convinced that it is a false reality (Breene et al., 2000).

The fantastic claim by a living person that he or she is dead is known as Cotardís delusion. People with Cotardís often doubt their own existence and the existence of the external world. These morbid delusions are often (paradoxically) accompanied by suicide attempts and ideations. Generally, Cotardís delusion produces feelings of unreality, visual recognition difficulty, and a belief that oneís body is rotting and malodorous (Young & Leafhead, 1996). There is some disagreement among researchers as the to causes of Cotardís delusion. Gerrans (2000) credits it to a reasoning deficit. Alternatively, Ramachandran and Blakeslee (1998) contend that it is simply a more severe form of the Capgras delusion, involving damage to more neural pathways. In yet another view, Young and Leafhead (1996) propose that it is a matter of attribution differences within the person, that is, people who are internally focused would be more likely to experience Cotardís and people who are externally focused would be more likely to experience Capgrasí.

Among the other misidentification syndromes there exists the following the disorders: intermetamorphosis, reverse intermetamorphosis, temporal reduplication, autoscopic phenomena, and mirrored-self misidentification. Intermetamorphosis delusions assert that a person has changed fully from one individual into another, the transformation is not simply a disguise. Reverse intermetamorphosis involves the belief that oneís self has been changed completely into another person, physically and mentally. In temporal reduplication, patients experience a persistent dťjŗ vu feeling, believing that particular events have happened previously (Weinstein, 1996). Note the similarity between temporal reduplication and the aforementioned incident of reduplicative paramnesia where the woman believed she had been mugged twice. The slight difference may be that in temporal reduplication, there is a belief that an event has occurred before it actually occurred, and in reduplicative paramnesia, there is a belief that the event occurred again after it actually occurred. These are some of the fine lines that create shades of difference between syndromes rather than discrete categories. Autoscopic phenomena, a variation on the Capgras delusion, are evidenced by a personís belief that they are an imposter of themselves. This time there is a parallel to reverse intermetamorphosis, except that in autoscopic phenomena, people are not wholly changed, but merely imposters (Weinstein, 1996). People who experience mirrored-self misidentification believe that the person in the mirror is another human being (who, coincidentally, looks much like themselves) (Breen et. al, 2000).

Though reduplicative phenomena may be relatively rare, they seem to have sparked the curiosity of neuroscientists for many years. A case of what has become known as Cotardís delusion may have been reported as far back as the eighteenth century. Later, in 1903, Arnold Pick diagnosed a patient with reduplicative paramnesia (Weinstein, 1996). Joseph Capgras continued the pioneering with some well documented cases of the now-named Capgrasí delusion (Breen et al., 2000; Weinstein, 1996). Until recently, there were but a few theories on the ďwhyĒ of misidentification delusions, and these pointed to purely psychological causes. In one early theory, these delusions were thought to be a guilt relief valve for a love-hate relationship; that is, one is free to hate a person they are supposed to love if that person is an imposter (Young, 2000). Alternatively, Ramachandran and Blakeslee (1998) cite an even more Freudian view of misidentification syndromes. It was thought that a traumatic event or injury brought to light our fully repressed but innate sexual love for the parent of the opposite sex. Because this feeling is so inappropriate and incongruent with society and oneís self concept, oneís defense mechanisms take over. In order to prevent mental catastrophe, the defense mechanisms evokehe delusion of misidentification. Therefore, it is not so terribly distressing to be sexually attracted to, say, oneís mother, if she is not really oneís mother but only an imposter. While it is a clever explanation, it is easily dismissed when, as happened to Ramachandran, a patient presents with the delusion that it is his dog that has been replaced by an imposter (Ramachandran & Blakeslee, 1998). Currently, there are more sophisticated and plausible theories on the table.

Ramachandran and Blakeslee (1998) propose that misidentification syndromes (particularly Capgrasí) are a result of neurological damage and messaging problems in the brain. They suggest that, while the brainís visual center (in the temporal cortex) may retain its ability to recognize faces, the affective portion of the brain is receiving proper information. The amygdala, which transmits these messages to the emotion controlling limbic system, may be damaged. This would explain why, for example, a male patient could believe that a person looks just like his mother, but then insist she is not. This is the only way the patient can account for his lack of emotion while in the presence of his mother. He simply doesnít feel any familiar connection with his mother; thus, she must be an imposter. Incidentally, this would also explain why people with delusional misidentification syndromes often claim that only their closest relatives are imposters, while acquaintances and other familiar people are not. To test his theory, Ramachandran measured the galvanic skin response of a patient with the Capgras delusion (and that of a control group) while they viewed different photos. Some of the photos were of close family members, and some were of strangers. As predicted, the patient showed the same low autonomic nervous system response to all photos, while the control group had a markedly higher response to the photos of family members. And since the patient had a wide range of normal emotion in everyday life, it is surmised that his limbic system was unaffected; that is, his lack of emotion toward his parents wasnít a blanket lack or inappropriate show of emotions as would be indicated in limbic system damage (Ramachandran & Blakeslee, 1998.)

Youngís (2000) research shows findings similar to those of Ramachandranís, and Young generally shares the same theory; however, Young has tried to explain the further question of Ďwhyí people experience a delusion of imposters instead of creating some other more plausible explanation for their lack of emotion toward close relatives. Young (2000) and his colleagues assert that the anatomical/neurological theory does not fully explain the delusion. They believe that there must be a unique combination of perceptual impairment and reasoning bias that creates the basis for these delusions (Young, 2000). According to Young (2000), the addition of a reasoning bias would fully explain why the delusions are formed and maintained.

Treatment and prognosis for delusional misidentification syndromes as a result of neurological damage vary widely. In some case studies, the patients recovered slowly over time (Weinstein, 1996; Ramachandran & Blakeslee, 1998). In other cases, especially in those of elderly patients, the delusions may continue or become worse, progressing into general dementia (Breen et al., 2000; Burgess, Baxter, Rose, & Alderman, 1996). Patients responded with varying success to an array of treatments, including: cognitive and behavioral therapies, electro-convulsive therapy, and the use of pharmaceuticals, such as anti-psychotics, anti-convulsants, neuroleptics, sedatives, and tranquilizers (Burgess et al., 1996; Ellis & Szulecka, 1996; Lewis-Lehr, Slaughter, Rupright, Singh, 2000; Weinstein; 1996; Young & Leafhead, 1996). Unfortunately, treatment effectiveness seems to be as unpredictable as recovery success.

At this seemingly immature stage of research into misidentification disorders, some profound and intriguing theories have cropped up. It is no surprise that much research has been devoted to reduplicative delusions, in spite of their relative rarity. Perhaps the bizarre and unusual nature of these syndromes simply awakens a curiosity in everyone, particularly neuroscientists. However, maybe these academicians are on a greater quest, pursuing clues to the ultimate mystery, and hoping to bridge the chasm between consciousness and the brain.

Breen, N., Caine, D., Coltheart, M., Hendy, J., & Roberts, C. (2000). Towards an understanding of delusions of misidentification: Four case studies. Mind and Language, 15 (1), 74-111. Retrieved February 28, 2002, from Ebscohost Academic Search Premier database. Burgess, P.W., Baxter, D., Rose, M., & Alderman, N. (1996). Delusional paramnesic misidentification. In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry (pp. 51-78). East Sussex, UK: Psychology Press.Ellis, H. D., & Szulecka, T. K. (1996). The disguised lover: A case of Fregoli delusion. In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry (pp. 39-50). East Sussex, UK: Psychology Press.Gerrans, P. (2000). Refining the explanation of Cotardís delusion. Mind and Language, 15 (1), 111-123. Retrieved February 28, 2002, from Ebscohost Academic Search Premier database.Halligan, P. W., & Marshall, J. C. (Eds.). (1996). Method in madness: Case studies in cognitive neuropsychiatry. East Sussex, UK: Psychology Press.Lewis-Lehr, M. M., Slaughter, J. R., Rupright, J., & Singh, A. (2000). The man who called himself Ďhockey stickí: A case report including misidentification delusions. Brain Injury, 14 (5), 473-479. Retrieved February 28, 2002, from Ebscohost Academic Search Premier database.Luzatti, C., & Verga, R. (1996). Reduplicative paramnesia for place with preserved memory. In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry (pp. 187-207). East Sussex, UK: Psychology Press.Pisani, A., Marra, C., & Silveri, M.C. (2000). Anatomical and psychological mechanism of reduplicative misidentification syndromes. Neurological Sciences, 21 (5), 324-329. Retrieved February 28, 2002, from Ebscohost Academic Search Premier database.Ramachandran, V. S., & Blakeslee, S. (1998). Phantoms in the brain: Probing the mysteries of the human mind. New York: William Morrow. Weinstein, E. A. (1996). Reduplicative misidentification syndromes. In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry (pp. 13-38). East Sussex, UK: Psychology Press.Young, A. W., & Leafhead, K. M. (1996). In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry (pp. 147-171). East Sussex, UK: Psychology Press.Young, A. W. (2000). Wondrous strange: The neuropsychology of abnormal beliefs. Mind and Language, 15 (1), 47-74. Retrieved February 28, 2002, from Ebscohost Academic Search Premier database.

Submitted 9/15/2002 9:32:58 AM
Last Edited 9/18/2002 1:35:47 PM
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