Capgras' syndrome

   Also known as Capgras syndrome, Capgras syndrome for persons, Capgras delusion, illusion des sosies, illusion of doubles, and illusion of false recognition. The eponym Capgras' syndrome refers to the French psychiatrist Jean Marie Joseph Capgras (1873-1950), who has been credited with being the first to describe the concomitant phenomenon in collaboration with his intern Jean Reboul-Lachaux in 1923. It was their French colleague Joseph Levy-Valensi who in 1929 proposed the eponymCapgras' syndrome. Capgras and Reboul themselves referred to this syndrome by the French term illusion des sosies (illusion of doubles). Today the term Capgras' syndrome is used to denote a condition characterized by the inability to identify a familiar person, even though one does recognize that person's facial and bodily characteristics. As a result, individuals with Capgras' syndrome tend to believe that the person in question has been replaced by a double (hence the name illusion of doubles). The syndrome is generally regarded as a type of hypo-identification, and classified as one of the *misidentification syndromes, or, more specifically, as one of the delusional reduplication syndromes. It has also been classified as an agnosia, and as a variant of reduplicative param-nesia (the latter condition being characterized by the affected person's conviction that a familiar place, or object, or person has been duplicated). Because of its association with various psychiatric and neurological disorders, doubts were long expressed about whether Capgras' syndrome deserves the nosological status of a syndrome. As to its pathophysiology, it has been suggested that Capgras' syndrome is associated with bifrontal cerebral cortical atrophy, and with the presence of one or more right parieto-occipital lesions. However, the right fusiform gyrus - which plays an important role in various stages of face recognition - has emerged as a possible candidate for the syndrome's primary neurophysio-logical correlate. A variant of the Capgras-type misidentification syndrome characterized by the conviction that one's house, or the building in which one currently resides (such as a hospital) has been replaced by a duplicate building, is known under the name Capgras for environment. The term Capgras for arm was introduced by the American neurologist and psychiatrist Todd Feinberg and his colleague David M. Roane to denotea variantof*asomatognosia characterized by misidentification of a part of one's body (i.e. an arm).

   References

   Capgras, J., Reboul-Lachaux, J. (1923). L'illusion des "sosies" dans un delire systematisé. Bulletin de la Société de Médecine Mentale, 11, 6-16.

   Ellis, H.D., Whitley, J., Luauté, J.-P. (1994). Delusional misidentification. The three original papers on the Capgras, Frégoli and intermeta-morphosis delusions. (Classic Text No. 17). History of Psychiatry, 5, 117-146.

   Feinberg, T.E., Deluca, J., Giacino, J.T., Roane, D.M., Solms, M. (2005). Right-hemisphere pathology and the self: Delusional misidentification and reduplication. In: The lost self. Pathologies ofthe brain and identity. Edited by Feinberg, T.E., Keenan, J.P. Oxford: Oxford University Press.