SPATIAL WORKING-MEMORY DEFICITS IN THE RELATIVES OF SCHIZOPHRENIC-PATIENTS

Background: Studies in nonhuman primates provide evidence that intact spatial working memory depends on the integrity of specific areas in t he prefrontal cortex. Patients with schizophrenia have been shown to b e impaired on spatial working memory tasks. Relatives of schizophrenic patients show a range of cognitive deficits in the absence of clinica l symptoms (eg, thought disorder, eye tracking dysfunctions). We predi cted that a significant proportion of relatives of schizophrenic patie nts would show deficits in working memory as measured by a delayed res ponse task. Methods: In experiment 1, we tested 18 schizophrenic patie nts, 15 first-degree relatives of schizophrenic patients, and 18 norma l control subjects on an oculomotor delayed response task. In experime nt 2, we assessed the performance of another group of 12 first-degree relatives of schizophrenic patients and 16 different normal control su bjects on a visual-manual delayed response task. Results: Relatives of schizophrenic patients showed significant deficits in working memory on both the oculomotor and visual-manual delayed response tasks. Concl usions: Some relatives of schizophrenic patients are impaired on tasks that tap spatial working memory and that implicate the prefrontal sys tem. The delayed response paradigm may be useful in elucidating the mu ltidimensionality of the schizophrenic phenotype.