3019PSY Module 6 Delusions

cognitive neuropsychology

the combination of cognitive psychology and neuropsychology with an emphasis on understanding the mind

cognitive neuropsychiatry

the application of cognitive neuropsychology methods to understand and explain disorders of higher cognition

delusion

a false belief based on incorrect inference about external / internal reality that is firmly sustained despite what almost everyone else believes and despite proof to the contrary

monothematic delusion

delusions concerning a single topic

encapsulated belief

beliefs that do not interact with the rest of a persons belief system

capgras delusion

the belief that people/ things close to the person have been replaced by an imposter

cerebral hemisphere disconnection hypothesis of capgras delusion

capgras occurs when information from either hemisphere fails to integrate

fregoli delusion

where a person believes they are being followed by known people in disguise

cotards delusion

where a person believes that they are dead

Hirsten & Ramachadran affective integration model for capgras

proposes that capgras is due to a failure of integration of information between the temporal lobes and limbic system; uses the “glow” metaphor

Ellis & Young/ Breen et al affective response model for capgras

proposes that capgras is due to abnormaly low autonomic arousal but normal facial recognition when viewing familiar faces, and that this mismatch creates the delusion

Ellis & Lewis modified affective response model for capgras

proposes that capgras occurs because of low levels of autonomic arousal, and specifies that the delusion results from a “feeling” that something is wrong, explaining why people with capgras cannot explain what is actually different bewteen the person and imposter

Coltheart (2007, 2010, 2011) two-factor theory for capgras

proposes that capgras is due to 2 factors: (1) low autonomic response to familiar faces, and (2) damage to the right lateral PFC causing an impaired belief evaluation system. This explains why the delusion actually occurs

Lucchilli & Spinner cross-modal disorder proposal of capgras

suggests capgras is a failure of the person recognition system rather than just facial recognition. This is due to a very brittle gestalt checking system that does not allow discordant information to be integrated from the person identity nodes and biographic information + damage to the right hemisphere = impaired belief evaluation system

affective response model for fregoli

suggests fregoli is due to a strong autonomic response to all faces, even unfamiliar ones, and that the delusion occurs to rectify this mismatch

two-factor theory of fregoli

factor 1: strong autonomic response to all faces

factor 2: damage to right lateral PFC = impaired belief evaluation system, therefore the person persists with the belief they are being followed by people in disguise

affective response model for cotards

suggests cotards is due to lack of autonomic responses for all stimuli (not just faces)

two-factor theory for cotards

factor 1: low autonomic response for all stimuli

factor 2: damage to the right lateral PFC = impaired belief evaluation system, therefore the person persists with the belief they are dead

delusions of the self

includes mirror self-misidentification, reverse intermetamorphosis, somatoparaphrenia, and alien control

mirror self-misidentification

the inability to recognise oneself, but not others, in the mirror

reverse intermetamorphosis

where a person believes they have physically and psychologically changed into another person

somatoparaphrenia

where a person believes their limb/s does not belong to them

alien control delusion

where a person believes their actions are under the control of someone else

two-factor theory of mirror-self misidentification

factor 1: a kind of facial recognition impairment extending to the self and possibly famous people, but not family members

factor 2: damage to the right lateral PFC = impaired belief evaluation system, therefore the person persists with the belief that it is not them in the mirror

two-factor theory of reverse intermetamorphosis

factor 1: some kind of physical change ignites confusion about personal identity

factor 2: damage to the right lateral PFC = impaired belief evaluation system, so the person persists with the delusion that they have changed into someone else

two-factor theory of somatoparaphrenia

factor 1: paralysis of the limb/s leads to the belief that it is disconnected from the body

factor 2: damage to the right lateral PFC = impaired belief evaluation system, so the person persists with the belief that the limb is not theirs

two-factor theory of alien control

factor 1: impaired self-monitoring action and sensory feedback link

factor 2: damage to the right lateral PFC = impaired belief evaluation system, so the person persists with the belief that their actions are being controlled by someone else

delusions of reduplication

includes reduplicative paramnesia of a person, place reduplication, and invisible doppleganger delusion

reduplicative paramnesia of a person

where a person believes that someone they know exists in two places/ states at once

place reduplication

the belief that a place has been duplicated and exists in two locations simultaneously

chimeric assimilation

the belief that two places have been combined

extravagant spatial localisation

where a person believes they are located in a different place than they actually are

invisible doppleganger delusion

where a person believes they have a clone or that they are a clone

two-factor theory of reduplicative paramnesia of a person

factor 1: disorientation for time and place due to a stroke

factor 2: damage to the right lateral PFC = impaired belief evaluation system, so the person persists with the belief that the person exists in two places / states at once

two-factor theory of place reduplication

factor 1: neurological damage causing deficits in memory, geographical/ visuospatial skills, and familiarity

factor 2: damage to the right lateral PFC = impaired belief evaluation system, so the person persists with the belief that the place has been duplicated

two-factor theory of invisible doppleganger delusion

factor 1: a neurological cause associated with thalamocortical and limbic loops affected the feeling of ownership over ones own body

factor 2: damage to the right lateral PFC = impaired belief evaluation system, so the person persists with the belief they have a clone or they are a clone