Towards an Understanding of Delusions of Misidentification: Four Case Studies

Abstract

Four detailed cases of delusions of misidentification (DM) are presented: two cases of misidentification of the reflected self, one of reverse intermetamorphosis, and one of reduplicative paramnesia. The cases are discussed in the context of three levels of interpretation: neurological, cognitive and phenomenological. The findings are compared to previous work with DM patients, particularly the work of Ellis and Young (1990;Young, 1998) who found that loss of the normal affective response to familiar faces was a contributing factor in the Capgras delusion. The four cases presented suggest that this particular deficit is not a critical factor in the development of other forms of DM.Delusions of misidentification (DM) include a variety of fascinating disorders in which there is a mistaken belief in the identity of oneself, other people, places or objects. They include: Capgras syndrome-the belief that other people, often close relatives, have been replaced by doubles or impostors; Fregoli syndrome-the belief that strangers are in fact known people in disguise; intermetamorphosis-the belief that someone has changed physically and psychologically into another person; reverse intermetamorphosis-the belief that there has been a physical and psychological change of oneself into another person; and reduplicative paramnesia-the belief that there are doubles of known people or places. This last delusion (reduplicative paramnesia) differs from Capgras delusion in that while reduplication is believed to have occurred, there is no sense of replacement. Thus, the impostor claim is not made in cases of reduplicative paramnesia. Patients with DM traverse the boundaries of psychiatry, neurology and neuropsychology and have been studied from the perspective of all three disciplines. 1 We are very grateful to TH, FE, DB, RZ and their families for their participation in this research. We would also like to thank Matthew Large for insightful discussion about the cases and referral of patient RZ, Virginia Arpadi for referring patient TH, David Sharpe for referring patient FE, and Robyn Langdon and Karalyn Patterson for helpful comments on an earlier draft of this paper.

Delusions and the Background of Rationality

“…The presumed difference in looks or behaviour between the real spouse or relative and the 'impostor' becomes evidence for the delusion. Often subjects attempt to describe the difference between the impostor and the spouse or relative in terms of slight discrepancies in the physical appearance, such as 'the eyes are too close' or 'she's too tall' (Breen et al, 2000). The obvious response to this line of argument is that the attempt to justify one's conviction is just a post-hoc reconstruction.…”

Phenomenology and delusions: Who put the ‘alien’ in alien control?

“…Similarly, the Cotard delusion (which involves the belief that one is dead or unreal in some way) may stem from a general flattening of affective responses to external stimuli (Ellis & Young, 1990), while the seed of the Frégoli delusion (the belief that one is being followed by known people who are in disguise) may lie in heightened affective responses to unfamiliar faces (Davies et al, 2001). Experience-based proposals have been provided for a number of other delusions (Breen et al, 2000;Breen et al 2001;Stone & Young, 1997;Maher, 1988;Davies, 2001;Davies et al, 2005;Langdon & Coltheart, 2000).…”

The Cognitive Approach to Delusions: Opportunities and Perspectives

“…Многие из подобных следствий этой модели были подтверждены [Young et al 1992;Breen et al 2000]. Однако в некоторых случаях пациен-ты переживали подобные перцептивные аномалии, но бредовой симпто-матики у них не было [Tranel et al 1995].…”