Neuropsychological functioning and jumping to conclusions in delusions.
BACKGROUND
It has been consistently demonstrated that delusions are related to jumping to conclusions (JTC), a data-gathering bias and potential candidate endophenotype of psychosis. Recent research suggests that JTC may be a marker of treatment response. However, we know little about the factors contributing to the occurrence of this reasoning bias. This study investigated the relationship between JTC and hypothesised deficits in working memory, employing standard well-validated neuropsychological tests, in people with current delusions.


METHODS
One hundred and twenty six people with schizophrenia spectrum psychosis and current delusions were assessed for current symptoms, and tested for JTC. We compared performance on tests of working memory in those with the reasoning bias and those without.


RESULTS
As expected, 30-40% of this sample of people with current delusions showed the JTC bias. There were no differences in premorbid IQ between those with and without the JTC reasoning bias. However, the performance of the JTC group was significantly worse on tests of working memory.


CONCLUSIONS
The JTC data-gathering bias is associated with impairments in working memory. New non-pharmacological interventions for people with delusions, designed to improve data gathering, may benefit from incorporating strategies to overcome deficits in working memory.
Department of Psychology, Institute of Psychiatry, King's College London, London, UK. Electronic address: philippa.garety@kcl.ac.uk.
Philippa
P
Garety
Eileen
E
Joyce
Suzanne
S
Jolley
Richard
R
Emsley
Helen
H
Waller
Elizabeth
E
Kuipers
Paul
P
Bebbington
David
D
Fowler
Graham
G
Dunn
Daniel
D
Freeman
D000293:Adolescent; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003702:Delusions / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D007600:Judgment; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000150:complications*; D055815:Young Adult
Delusions; Jumping to conclusions; Schizophrenia-spectrum psychosis; Working memory