Cognitive dimensions in first-episode schizophrenia spectrum disorders

Abstract

Background: The severity and pattern of cognitive deficits in epidemiological cohorts of patients with first-episode schizophrenia spectrum disorders still remains unclear. We aimed to characterize the basic cognitive functioning of a representative sample of patients with a first-episode schizophrenia spectrum disorders.

Method: One hundred thirty-one patients experiencing first-episode psychosis and 28 healthy volunteers were administered a comprehensive neuropsychological evaluation. To reduce the number of cognitive test measures into meaningful cognitive dimensions, before analyzing differences between patient and healthy volunteer samples, exploratory factor analysis was carried out on data collected in patients group. The method of extraction was Principal Components Analysis with oblique rotation.

Results: An eight-factor model including verbal learning/memory, verbal comprehensive abilities, speed of processing/executive functioning, motor dexterity, motor speed, sustained attention, and impulsivity emerged. A significant below average performance in all cognitive dimensions, except impulsivity, was found. Patient's performance in speed of processing/executive functioning, motor dexterity and sustained attention dimensions exceeded one standard deviation below healthy comparison subjects.

Conclusions: At early stages of the illness, patients display a marked impairment in several functionally relevant cognitive domains.