Neuropsychological functioning in first-episode schizophrenia.
BACKGROUND
Identifying neurocognitive subtypes in schizophrenia may help establish neurobiologically meaningful subtypes of the disorder, but is frequently confounded by differences in intellectual function between individuals with schizophrenia and controls.


OBJECTIVE
To examine neuropsychological performance in individuals with epidemiologically based, first-onset schizophrenia and intellectually matched controls.


METHODS
Using standard IQ and reading tests, we examined the proportions of 101 people with epidemiologically derived, first-onset schizophrenia/schizoaffective disorder and 317 community controls, falling into three a priori defined intellectual categories: 'stable good', 'deteriorated poor' and 'stable poor'. Neuropsychological function was compared between intellectually matched participants with schizophrenia and control subgroups.


RESULTS
Multiple deficits in executive function, processing speed and verbal memory, but not visual/spatial perception/memory, were detected in all participant groups with schizophrenia compared with controls. The average effect size across the affected domains ranged from small to medium to large in the stable good, deteriorated poor and stable poor subgroups of participants with schizophrenia, respectively.


CONCLUSIONS
Compared with intellectually matched controls, people with epidemiologically derived, first-onset schizophrenia/schizoaffective disorder show multiple deficits in executive function, processing speed and verbal memory.
Department of Psychiatry, NIHR Biomedical Research Centre for Mental Health, South London and Maudsley NHS Foundation Trust and Institute of Psychiatry, King's College London, London. e.kravariti@iop.kcl.ac.uk
Eugenia
E
Kravariti
Kevin
K
Morgan
Paul
P
Fearon
Jolanta W
JW
Zanelli
Julia M
JM
Lappin
Paola
P
Dazzan
Craig
C
Morgan
Gillian A
GA
Doody
Glynn
G
Harrison
Peter B
PB
Jones
Robin M
RM
Murray
Abraham
A
Reichenberg
D000293:Adolescent; D000328:Adult; D000368:Aged; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000453:epidemiology / Q000523:psychology*; D007360:Intelligence / Q000145:classification*; D008297:Male; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000145:classification / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D014706:Verbal Learning; D055815:Young Adult