Spatial working memory ability is a marker of risk-for-psychosis

Background. Working memory has been identified as a core cognitive deficit in schizophrenia that is associated with negative symptoms, but it is unclear whether it is impaired prior to onset of psychosis in symptomatic patients. Method. Thirty-eight young people at ultra high-risk (UHR) of developing psychosis (of whom nine later became psychotic) were compared with 49 healthy controls on tests of spatial working memory (SWM) and delayed matching-to-sample (DMTS). Results. Both SWM and DMTS performance was significantly poorer in the UHR groups. Those who later became psychotic generally performed more poorly than those who did not, although this did not reach significance for any measure. A significant association between SWM errors and negative symptoms was seen in the later-psychotic group only (P=0.02). Conclusions. Spatial working memory abilities are impaired in those at high-risk for psychosis. The relationship between working memory and negative symptoms may be useful as a predictive tool.