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