DELUSIONS OF MISIDENTIFICATION: A COGNITIVE NEUROPSYCHIATRY APPROACH

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DELUSIONS OF MISIDENTIFICATION A COGNITIVE
NEUROPSYCHIATRY APPROACH

• Hadyn D Ellis
• Cardiff University
• UK
• EllisH_at_cardiff.ac.uk

Athens, 2005
Advances in Psychiatry
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Cognitive Neuropsychiatry

• Cognitive Neuropsychiatry involves the use of
  cognitive models to understand certain psychotic
  symptoms. Further, where the models are
  inadequate, they are modified to fit the data.
• One of the appealing aspects of the Cognitive
  Neuropsychiatric method is that it can generate
  testable predictions. This contrasts with
  traditional, post hoc psychodynamic approaches
  that rarely, if ever, produce falsifiable
  hypotheses.

Ellis, 1991 David 1993
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Delusional Misidentification Syndromes Paraprosopi
a faces seem horribly distorted Intermetamorpho
sis faces/objects change to look like
someone/something else Frégoli no change in
appearance but the belief that the person is
someone else in disguise Capgras belief that
people often, but not exclusively, close have
been substituted by impostor/robot. Capgras for
objects/places/animals also possible (cf.
Reduplicative Paramnesia)
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Paraprosopia

• Paraprosopia when a face appears to transform
  within seconds into a grotesque mask, often
  described by patients as a "monster", "vampire"
  or "werewolf" Krauss, 1852. Most likely to be
  reported by schizophrenic children but also
  observed in adults (e.g. Daniel Paul Schreber,
  1842-1911, President of the Court of Appeal in
  Dresden, saw two men "as devils with particularly
  red faces").
• AUTOPARAPROSOPIA paraprosopia for own face.

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Intermetamorphosis Courbon and Tusques (1932)
described Sylvie G, a 49-year-old woman who
claimed that objects and animals seemed
altered. People could change gender as she
looked at them. Many people looked like her son
or her aunt. She could distinguish them from her
true son only by examining their feet (his were
large and were invariably shod in dirty
shoes). Her husband might change appearance into
that of a neighbour (all except his eye colour
and missing finger). There were no further
reports of intermetamorphosis for 46 years, since
when five cases have been described, including
three by Young et al. (1990).
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The Frégoli Delusion

• First reported by Courbon and Fail (1927). They
  described a 27-year-old woman, a domestic servant
  with a passion for the theatre, who developed the
  delusion that the actresses Robine and Sarah
  Bernhardt were persecuting her in the guise of
  others.
• They suggested the term Frégoli delusion with
  reference to the celebrated Italian mimic
  Léopoldo Frégoli.
• The essential feature of this delusion is that
  there is no belief of any physical change
  instead the patient believes that his/her
  persecutors can invade the body of others.
• We have no figures on the incidence of the
  Frégoli delusion, except that it is more rare
  than the Capgras delusion.

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The Capgras Delusion

• First reported by Kahlbaum (1866) but more
  extensively described by Capgras and colleagues
  (1923, 1924). The essential symptom is that
  patients assert that others usually, but not
  necessarily, close to them have been replaced by
  impostors, doubles, robots, etc.
• Mme M, aged 53 years, believed husband, daughter
  and many others had been replaced by doubles,
  often many times. She also manifested delusions
  of paranoia and grandeur.
• The Capgras delusion is classified as a dangerous
  delusion. It occurs in all societies and in
  children as well as adults. It may be related to
  the neurological syndrome REDUPLICATIVE
  PARAMNESIA.

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The Psychodynamic Approach

• Capgras, and most who followed him, offered
  various psychoanalytic explanations for the
  Capgras delusion.
• Enoch and Trethowan (1979) and Berson (1983)
  identified specific problems whereby, in order to
  deal with overwhelming, guilt-ridden ambivalence
  about specific others, patients "split" into good
  and bad (i.e. the double).
• Problems
• (i) like all psychodynamic theories it is post
  hoc and non-predictive
• (ii) sometimes it is quite clear that there is
  no prior ambivalence nor is the double
  necessarily viewed in a negative way
• (iii) although the ambivalence argument may be
  stretched to misidentification delusions for
  ANIMALS, it provides a less credible account of
  MISIDENTIFICATION OF INANIMATE OBJECTS.

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Aetiology of DMS
Paranoid Schizophrenia Depression Cerebral
Infarction Brain Atrophy Tumours Alzheimers
Disease AIDS Encephalitis Migraine Epilepsy Diabet
es Toxic States Puerperal Psychosis Metabolic
Disorders Deficiency States (B12) Medications
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Simplified Modal Model of Face Recognition
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Simplified Modal Model of Face Recognition
Initial Structural Encoding
paraprosopia
Person Identity Nodes
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Simplified Modal Model of Face Recognition
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Simplified Modal Model of Face Recognition
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Capgras Right Hemisphere
Cutting (1985) - Capgras failure
in identification process, i.e., result of RH
dysfunction Bidault et al. (1986) - poor scores
on face processing tasks Feinberg Shapiro
(1989) - 26 cases, only two LH damage alone.
SPECT data during CD. An average 20 decrease in
uptake was observed in the right parietal
cortical area, with 11 left-right asymmetry
(normal lt 4)
(Lebert et al., 1994)
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Ellis et al. (1993) Tachistoscopic
Presentation of Pairs of Faces
Bilateral
LVF
RT
RVF
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Prosopagnosia

• Loss of recognition for once-familiar faces (but
  not voices), usually following right
  ventro-medial damage
• Evidence of covert recognition

• SCR
• Face-naming priming
• Face interference
• Name re-learning

• Claim that these covert effects involve common
  mechanism

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SCRs to Familiar and Unfamiliar Faces Presented
Supraliminally and Subliminally
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Capgras as a Mirror-Image of Prosopagnosia
Limbic System
Visual Cortex
Bauers (1984) Dual Routes to Face Recognition
Limbic System
Visual Cortex
//
Prosopagnosia
//
Limbic System
Visual Cortex
Capgras Delusion
Ellis Young, 1990
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Prediction

• Capgras patients will not show the normally
  appropriate skin conductance response to familiar
  faces, despite the fact that these will be
  overtly recognized.

(Ellis Young, 1990)
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Experiment

• 5 patients with Capgras delusion
• 5 matched patients with other delusions
• 5 controls
• Presented (randomly) with
• 5 famous faces
• 25 unfamiliar faces

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Mean range-corrected SCR amplitude to familiar
and unfamiliar faces for normal
controls,psychiatric controls and people with
Capgras delusion.
Adapted from Ellis et al. (1997) Proc. R. Soc. B
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Mean SCR amplitude (uS) across five presentations
of an auditory tone for normal controls and
people with Capgras delusion.Ellis et al.
(1997) Proc. R. Soc. B
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Modified Face Recognition Model
(Ellis Lewis, 2001)
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CAPGRAS DELUSIONA Two-Stage Model

• Disruption/damage to the usual affective linkage
  to familiar face recognition a sufficient
  explanation? (cf. Maher, 1974)
• Tranel et al. (1995) fronto ventromedial lesions
  -gt no differential SCRs to familiar and
  unfamiliar faces but no Capgras delusion
• Additional stage, involving attribution seems
  likely (Ellis Young 1996 Young de Pauw, 2002)
• Attribution steered by paranoia (cf. Cotards
  where delusion may result from depression)
  (Young, 1997 Gerrens, 2000)
• Also an inability to revise the bizarre
  belief-despite evidence

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Summary

• The Cognitive Neuropsychiatric approach to
  monothematic delusions can be successful
• Delusions of misidentification may be explained
  by a model of normal face recognition
• However, for the Capgras delusion, the model
  itself must be altered to include emotional
  recognition of familiar others
• For Capgras delusion to develop it may be
  necessary for dysfunction to occur at

• a perceptual/cognitive level
• and
• (b) an attribution/judgement stage of decision
  making

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THE END
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Capgras Syndrome A Dangerous Delusion

• Blount (1986) studied 50 schizophrenics in a
  maximum security facility, three of whom
  manifested symptoms of Capgras syndrome.

Two have killed persons, both brutally. One
bludgeoned and then decapitated his 82 year
old stepfather (explaining) he had been
searching for batteries and microfilm in his
head to take to court to prove he was a robot
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