Capgras Syndrome: Agnosia of Identification and Delusion of Reduplication

Abstract

In the Capgras syndrome (CS) there is a natural dissociation between recognition and identification and it deserves to be designated as an agnosia of identification. Joseph Capgras who first introduced this concept of agnosia, also suggested that the syndrome might be studied within the framework of ‘mÉconnaissance systÉmatique’ (translated here as systematic unawareness), thus anticipating a type of interpretation in which the basis of CS (and other delusional misidentification syndromes) would be a lack of corporeal and/or egocentric space awareness. From two examples, it is suggested that the basic phenomenon of unawareness may be due to sensory deprivation. A particular process of awareness concerning personal objects is hypothesized which would explain the specific delusion of reduplication that occurs when these objects are misidentified.

Implicit Recognition of Familiar and Unfamiliar Faces in Schizophrenia: A Study of the Skin Conductance Response in Familiarity Disorders

“…Our study addressed the crucial question of whether FDs in patients with schizophrenia are more apparent with individuals close to the person considering the well-documented clinical description of this delusion ( 2 – 4 ). To the best of our knowledge, the present study is the first to investigate the SCR properties of FDs in patients with schizophrenia with respect to familiarity status using personally specific familiar faces and, therefore, ecologically valid face stimuli.…”

“…These patients often have persecutory delusions centered upon these relatives or friends. The most commonly described misidentification disorder is Capgras syndrome ( 3 , 4 ). Patients with Capgras syndrome recognize specific familiar faces but have the delusional belief that the familiar person is an impostor or a clone appearing as whom they claim to be.…”

“…However, the sample size was too small for a definitive conclusion; only five patients with Capgras syndrome were tested. Moreover, Capgras syndrome is described as affecting the recognition of close people who are affectively related to the patient ( 2 – 4 ). Furthermore, famous people are not always associated with a strong emotional investment ( 14 ).…”