SummarySeventeen schizophrenic patients with tardive dyskinesia (TD) and 33 schizophrenics without tardive dyskinesia were examined by psychological tests of intellectual function and EMI scans were performed. The group as a whole were found to be demented and 31 out of 45 had abnormalities on the scan. On a learning test the tardive dyskinesia group did significantly worse and using a measured parameter of the scan (the Ventricular Index) the tardive dyskinesia group had more abnormality. It is suggested that the higher incidence of pathology in the tardive dyskinesia group may be related to chronic neuroleptic toxicity.