suspicious minds nigel blackwood institute of psychiatry, kings college london
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Suspicious Minds
Nigel Blackwood
Institute of Psychiatry, Kings College London
Cognitive Neuropsychiatry
Psychopathology
Cognitive/Psychological Abnormality
Functional Neuroanatomy/Neurochemist
ry
‘A false judgement; it is held with incomparable subjective certainty; there is an imperviousness to other experiences and to compelling counter-argument; the content is impossible’Jaspers, 1913
Persecutory Delusions: the categorical approach
Persecutory Delusions:the dimensional approach
Mentalising errors
Aberrant determination of self-relevance
Jumping-to-conclusions reasoning bias
Self-serving attributional bias
Blackwood Am J Psych 2001
Neuroimaging of reality distortion
Liddle 1992; Kaplan 1993; Ebmeier 1993; Sabri 1997
The determination of self-relevance
In the deluded state, ambiguous social data are suffused with potential
meaning for the self
Patients with persecutory delusions selectively attend to threat-related stimuli (Bentall 1989; Fear 1996;
Leafhead 1996)
Patients with persecutory delusions make inflated estimates of the
likelihood of future threatening events (Corcoran, 2006)
The determination of self-relevance
Abnormal cingulate gyrus activation in the determination of self-
relevance
Normal subjects> deluded subjects, self>otherVentral anterior cingulate 0,34,4
Z=4.06
Impaired self-reflection in the deluded state
Abnormal cingulate gyrus activation in the determination of self-
relevanceDeluded subjects> normal subjects, self>otherPosterior cingulate 8, -46, 14Z=3.60
Ambiguously self-relevant material is encoded as emotionally salient to a greater extent in the deluded
state
Abnormal cingulate gyrus activation in the determination
of self-relevance
This accounts for the deluded patient’s subjective experience that a greater
array of ambiguous social data is suffused with potential meaning for the
self: erroneous resolution of this ambiguity in favour of the default ‘this is salient’ position occurs when self-
states are not adequately represented
Blackwood Psych Med 2004
The jumping-to-conclusions reasoning bias
Inductive inferences aid decision making under conditions of
uncertainty
They employ judgements of probability or likelihood
Deluded subjects show a data gathering bias in inductive reasoning
tasks
The bias is more pronounced with emotionally salient material
The jumping-to-conclusions reasoning
bias
The cerebellum and decision making under uncertainty
From motor control to inferential thought
Internal working models of uncertain events in the world
Pegboard task Kim 1994
Conceptual reasoning task derived from WCST Rao 1997
Formation and application of inductive categorisation rule Goel 2000
Blackwood Cognitive Brain Research 2004
Impaired cerebellar modulation of inductive inferences in the deluded
state
‘Dysmetria of thought’ may account for the jumping-to-conclusions reasoning bias in the
deluded state
Normal subjects> deluded subjects, probabilistic reasoning>counting
Left Lobule VI Cerebellar Cortex -8, -68, -20 Z=3.04
Self-serving attributional bias
Humans use causal attributions to infer the most likely cause of events in the social world
The self-serving bias describes the tendency of normal subjects to attribute the causation of positive events internally (‘I am responsible’) and negative events externally (‘Other people
or situational factors are responsible’)
Patients with persecutory delusions show an exaggeration of this self-serving bias
Self-serving attributional bias
Self-serving attributional bias
The dorsal striatum and the self-serving attributional bias
Normal subjects (n=8)
Right caudate nucleus 8 –7 17 6.82
Left caudate nucleus -6 –1 17 5.41
The attributions in the self-serving bias are motivated social beliefs
Blackwood Neuroimage 2003
Mentalising abnormalities in psychosis
A domain specific problem (False beliefs vs false maps, Pickup 2001)
Poor performance: under vs over mentalising?
Poor performance: explicit vs implicit?
A problem with conscious reflection upon states of mind?
Mentalising in psychosis
Which part(s) of the network involving medial prefrontal cortex (paracingulate cortex), TPJ in the STS and temporal poles is (are) compromised in the psychotic state?
Anticipation of threat (Anticipation social events task)
Explanatory style (ASQ)
Self-esteem (Nugent & Thomas)
Emotion (HADS)
ToM (intentional deception to 2nd order level)
JTC (beads in bottle and social variant)
IQ (WAIS vocabulary, matrix reasoning, digit span)
Bentall, Archives General Psychiatry, in press
How are these abnormalities inter-related?
PARB ANTIC
GLOB
COG_P DEP_S
INTFUN EMDYS
PAR
ToMD
STAB
JTC
.92
-.39
.85
.68
.60
.72
.78
.82 .72
-.07
.46
The cognitive structure of persecutory delusions across
diagnoses
Cognitive NeuropsychiatryPersecutory Delusion
Dopamine sensitisation
CBT approaches
Specificity and durability?
eg Kuipers 1997; Tarrier 1993; Sensky 2000
Developing alternative explanations of Sx
Peripheral questioning, graded reality testing, inference chaining
New approaches
Cognitive neuropsychiatric models of persecutory delusions
Questions? n.blackwood@iop.kcl.ac.uk
Cognitive neuropsychiatric models help to bridge the explanatory gap between functional neuroanatomy/chemistry and psychopathology
A functional neuroanatomy of mentalising abnormalities in psychosis remains to be
established
CBT and cognitive remediation may be useful adjuncts to antipsychotic medication…tailored approaches to the fundamental deficits may be
of particular benefit
The End
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