Approaching Delusional Misidentification Syndromes as a Disorder of the Sense of Uniqueness

Abstract

Co-occurrence of the different types of delusional misidentification syndromes (DMS) implies a common pathogenetic substrate. Until now, theoretical explanations have strained to produce a collective approach, but have been trammeled by the initial definition of the syndromes (Capgras/Fregoli) that originated from the attribution of causal significance to the element of familiarity towards the misidentified object. In this article, we present two cases illustrating the co-occurrence of the syndromes and we attempt to propose a new approach to DMS. We hypothesize that a common potential pathogenetic factor underlying DMS could be a disorder of the sense of uniqueness. The ability to attribute uniqueness to the self and to surrounding people, objects, or places is a principal property of the adaptable mind that acts as a matrix for the identification process. We propose that although the term ‘identity’ encompasses the concept of uniqueness, this must be accomplished somewhere in a model of semantic processing of identity. Our approach is questioning the current view that this sequential stage is the PIN stage in the functional model of face recognition by Bruce and Young, and we attempt to see the disordered sense of uniqueness within the evolved form of the model of face recognition and delusional misidentification introduced by Ellis and Lewis. We propose that such a disturbance could result in an unstable identification process, vulnerable to discrepancies in perceptual, emotional, or memory input caused by psychotic or organic mental states, thus resulting in a breakdown of the identification process that inevitably leads to a delusion of denial of identity, or to a delusion of ‘doubles’.

Capgras delusion: An interactionist model

“…In contrast, the Capgras husband's claim is categorical: ''That woman is an impostor". This is often 7 For an interesting development of Ellis and Lewis's model, in which delusional beliefs are explained in terms of a disorder of a sense of uniqueness, see Margariti and Kontaxakis (2006). 8 The earlier studies by Ellis et al and Hirstein and Ramachandran used famous faces rather than faces of the patient's family and friends.…”

Shared multisensory experience affects Others' boundary: The enfacement illusion in schizophrenia

“…Differently, patients extended in the same way both the Self and the Other toward their respective different poles, as they showed an equal increment in the number of frames attributed both to the Self and to the Other after EI. Indeed, schizophrenia patients often reportedly showed a disordered sense of uniqueness, assigned not only to the Self but also to surrounding people (Cutting, 1991;Margariti and Kontaxakis, 2006). Coherently, at a psychopathological level delusional misidentification syndromes (i.e., Capgras and Frégoli syndromes), which represent this blurred sense of uniqueness, occur primarily in schizophrenia.…”

The Fregoli Delusion: A Disorder of Person Identification and Tracking

“…Here, there is no known person involved at all, so this appears to be a generic sort of persecutory delusion. We likewise excluded a case where the patient believed that “freemasons from Athens” were appearing as his neighbor to get close to him to try to harm him (Margariti & Kontaxakis, ). In this case, there was no clear indication that the delusion involved any particular freemasons who were known to the patient.…”