What is Cognitive Neuropsychiatry?

Introduction

Cognitive neuropsychiatry is a growing multidisciplinary field arising out of cognitive psychology and neuropsychiatry that aims to understand mental illness and psychopathology in terms of models of normal psychological function.

Background

A concern with the neural substrates of impaired cognitive mechanisms links cognitive neuropsychiatry to the basic neuroscience. Alternatively, CNP provides a way of uncovering normal psychological processes by studying the effects of their change or impairment.

The term “cognitive neuropsychiatry” was coined by Prof Hadyn Ellis (Cardiff University ) in a paper “The cognitive neuropsychiatric origins of the Capgras delusion”, presented at the International Symposium on the Neuropsychology of Schizophrenia, Institute of Psychiatry, London (Coltheart, 2007).

Although clinically useful, current syndrome classifications (e.g. DSM-IV; ICD-10) have no empirical basis as models of normal cognitive processes. No neuropsychological accounts of how the brain ‘works’ would ever be complete without a cognitive level of analysis. CNP moves beyond diagnosis and classification to offer a cognitive explanation for established psychiatric behaviours, regardless of whether the symptoms are due to recognised brain pathology or to dysfunction in brain areas or networks without structural lesions.

CNP has been influential, not least because of its early success in explaining some previously bizarre psychiatric delusions, most notably the Capgras delusion, Fregoli delusion and other delusional misidentification syndromes. The Capgras delusion is “explained as the interruption in the covert route to face recognition, namely affective responses to familiar stimuli, localised in the dorsal route of vision from striate cortex to limbic system. According to standard molecular hypotheses, acute delusions are the result of a dysregulated activity of some neuromodulators.”

Additionally, the study of cognitive neuropsychiatry has shown to intersect with the study of philosophy. This intersection revolves around a reconsideration of the mind-body relationship and the contemplation of moral issues that can arise by fields such as neuropsychopathology. For example, it has been under consideration whether or not Parkinson’s patients should be held morally accountable for their physical actions. This discussion and study has taken place due to the discovery that under certain circumstances, Parkinson’s patients can initiate and control their own movement. Examples such as this are cause for difficult judgement calls, i.e. “about who is mad and who is bad” (Stein 1999). Cognitive neuropsychiatry has also explored the difference between implicit and explicit cognition, especially in catatonic patients. For more information on the bridge between neuropsychiatry and philosophy see (e.g. Stein, 1999).

References

Coltheart, M. (2007) The 33rd Sir Frederick Bartlett Lecture Cognitive Neuropsychiatry and Delusional Belief. Quarterly Journal of Experimental Psychology. https://doi.org/10.1080/17470210701338071.

Stein, D. (1999) Philosophy, Psychiatry, & Psychology 6.3, pp.217-221. https://www.researchgate.net/publication/236774712_Philosophy_and_Cognitive_Neuropsychiatry.

What is Delusional Misidentification Syndrome?

Introduction

Delusional misidentification syndrome is an umbrella term, introduced by Christodoulou (in his book The Delusional Misidentification Syndromes, Karger, Basel, 1986) for a group of delusional disorders that occur in the context of mental and neurological illness.

Refer to Cognitive Neuropsychiatry.

Background

They all involve a belief that the identity of a person, object, or place has somehow changed or has been altered. As these delusions typically only concern one particular topic, they also fall under the category called monothematic delusions.

This psychopathological syndrome is usually considered to include four main variants:

  • The Capgras delusion is the belief that (usually) a close relative or spouse has been replaced by an identical-looking impostor.
  • The Fregoli delusion is the belief that various people the believer meets are actually the same person in disguise.
  • Intermetamorphosis is the belief that an individual has the ability to take the form of another person in both external appearance and internal personality.
  • Subjective doubles, described by Christodoulou in 1978 (American Journal of Psychiatry 135, 249, 1978), is the belief that there is a doppelgänger or double of themselves carrying out independent actions.

However, similar delusional beliefs, often singularly or more rarely reported, are sometimes also considered to be part of the delusional misidentification syndrome. For example:

  • Mirrored-self misidentification is the belief that one’s reflection in a mirror is some other person.
  • Reduplicative paramnesia is the belief that a familiar person, place, object, or body part has been duplicated. For example, a person may believe that they are in fact not in the hospital to which they were admitted, but an identical-looking hospital in a different part of the country, despite this being obviously false.
  • The Cotard delusion is a rare disorder in which people hold a delusional belief that they are dead (either figuratively or literally), do not exist, are putrefying, or have lost their blood or internal organs.
    • In rare instances, it can include delusions of immortality.
  • Syndrome of delusional companions is the belief that objects (such as soft toys) are sentient beings.
  • Clonal pluralisation of the self, where a person believes there are multiple copies themselves, identical both physically and psychologically but physically separate and distinct.

There is considerable evidence that disorders such as the Capgras or Fregoli syndromes are associated with disorders of face perception and recognition. However, it has been suggested that all misidentification problems exist on a continuum of anomalies of familiarity, from déjà vu at one end to the formation of delusional beliefs at the other.