Cognitive dysfunction in first-episode psychosis: the processing speed hypothesis.
BACKGROUND
Speed of processing is a cognitive process underlying cognitive dysfunction in people with chronic schizophrenia.


OBJECTIVE
To investigate the contribution of speed of processing to the cognitive deficits observed in a representative large sample with first-episode schizophrenia.


METHODS
People with a diagnosis of first-episode schizophrenia-spectrum disorders (n=26) and healthy controls (n=28) were compared on several cognitive measures before and after controlling for speed of processing.


RESULTS
Before controlling for speed of processing, patients and controls differed significantly on all cognitive measures. All significant differences in cognitive functioning disappeared when the result of the Digital Symbol Substitution Test was included as an additional covariate.


CONCLUSIONS
Speed of information processing may be considered a core cognitive deficit in schizophrenia and might be mediating a broader diversity of cognitive disturbances.
Department of Psychiatry, School of Medicine, Hospital Universitario Marqués de Valdecilla, University of Cantabria, Planta 2a, Edificio 2 de Noviembre, Avda, Valdecilla s/n, 39008, Santander, Spain.
José Manuel
JM
Rodríguez-Sánchez
Benedicto
B
Crespo-Facorro
Cesar
C
González-Blanch
Rocío
R
Perez-Iglesias
José Luis
JL
Vázquez-Barquero
D000293:Adolescent; D000328:Adult; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011618:Psychotic Disorders / Q000523:psychology*; D011930:Reaction Time; D012565:Schizophrenic Psychology