Generalized and specific neurocognitive deficits in prodromal schizophrenia

Background: Neurocognitive deficits are considered to be central to the pathophysiology of schizophrenia, and the neurodevelopmental model suggests That such deficits precede full-blown psychosis. The present study examined performance on a broad neuropsychological battery of young subjects considered to be at clinical high risk for schizophrenia, who were subsequently followed to determine clinical outcome. Methods: Subjects were 38 clinical high-risk patients (58% male patients; mean age =.16.5) and 39 sex- and age-matched healthy control subjects. At baseline, all high-risk patients bad attenuated (subpsychotic) schizophrenialike positive symptoms. Clinical follow-up data of at least 6 months duration was available on 33 patients, of whom 12 developed nonaffective psychotic disorders. Results: At baseline, clinical high-risk patients bad significantly impaired global cognitive performance relative to control subjects and to estimates of their own prior intellectual functioning. Measures of verbal memory and executive functioning/working memory showed significantly greater impairments; visuospatial functioning was relatively spared. Prodromal patients who later developed psychosis bad significantly lower verbal memory scores at baseline compared with, patients who remained nonpsychotic. Conclusions: Verbal memory deficits may be an important factor for the development of schizophrenia-spectrum psychotic disorders, possibly indicating the presence of a prefrontal-hippocampal neurodevelopmental abnormality. Generalized neurocognitive impairment may be a nonspecific vulnerability marker.