The Effect of Nitric Oxide on Spatial Working Memory in Patients With Schizophrenia - Pilot Study

Spatial working memory (ability to remember where objects are in space) is impaired in patients with schizophrenia. It is thought that this impairment occurs due to problems with the chemical messenger (neurotransmitter), glutamate, and the N-methyl-D-aspartate (NMDA) glutamate receptor, particularly in the hippocampal brain region. NMDA receptor activation leads to increases in the release of the second messenger Nitric Oxide. Impaired NMDA receptor function would therefore be predicted to lead to reductions in Nitric Oxide production. Recent work suggests that a drug, sodium nitroprusside, which releases nitric oxide, enhances some aspects of cognition in schizophrenia (specifically related to negative symptoms). In this study, the investigators will test the hypothesis that sodium nitroprusside improves spatial working memory in patients with schizophrenia. 15 patients will receive sodium nitroprusside, and 15 will receive a nonactive compound (placebo). Their performance on a spatial working memory task will be tested before and after administration of sodium nitroprusside or placebo.