EXECUTIVE FUNCTION IN FIRST-EPISODE SCHIZOPHRENIA

Background. We tested the hypothesis that schizophrenia is primarily a frontostriatal disorder by examining executive function in first-epis ode patients. Previous studies have shown either equal decrements in m any cognitive domains or specific deficits in memory. Such studies hav e grouped test results or have used few executive measures, thus, poss ibly losing information. We, therefore, measured a range of executive ability with tests known to be sensitive to frontal lobe function. Met hods. Thirty first-episode schizophrenic patients and 30 normal volunt eers, matched for age and NART IQ, were tested on computerized test of planning, spatial working memory and attentional set shifting from th e Cambridge Automated Neuropsychological Test Battery. Computerized an d traditional tests of memory were also administered for comparison. R esults. Patients were worse on all tests but the profile was non-unifo rm. A componential analysis indicated that the patients were character ized by a poor ability to think ahead and organize responses but an in tact ability to switch attention and inhibit prepotent responses. Pati ents also demonstrated poor memory, especially for free recall of a st ory and associate learning of unrelated word pairs. Conclusions. In co ntradistinction to previous studies, schizophrenic patients do have pr ofound executive impairments at the beginning of the illness. However, these concern planning and strategy use rather than attentional set s hifting, which is generally unimpaired. Previous findings in more chro nic patients, of severe attentional set shifting impairment, suggest t hat executive cognitive deficits are progressive during the course of schizophrenia. The finding of severe mnemonic impairment at first epis ode suggests that cognitive deficits are not restricted to one cogniti ve domain.