We scanned 18 patients with schizophrenia who had never received neuroleptic medication and 20 age- and sex-matched controls by positron emission tomography with 18-F-fluorodeoxyglucose (fludeoxyglucose F 18) as a tracer of glucose metabolism. Subjects performed the Continuous Performance Test during 18-F-fluorodeoxyglucose uptake. Scan results were converted to metabolic rates, and computer algorithms were used to identify cortical regions. Previous reports of relative hypofrontality in schizophrenia were confirmed, indicating that this finding is not an artifact of previous treatment. Significantly reduced ratios of inferior and medial frontal regions to occipital cortex were found, together with diminished metabolism in the basal ganglia. This suggests the presence of a combined frontostriatal dysfunction in schizophrenia.