Abstract:The brains of 55 schizophrenic patients and 65 controls were examined using computerized tomography scans. The width of the inter‐hemispheric fissure and the third ventricle, and the volume of the lateral ventricles in the schizophrenic patients were significantly larger than those obtained in the controls. The extension of the width of the interhemispheric fissure and the increase in the volume of the lateral ventricles in the schizophrenic patients were assumed to be caused not by aging but by the schizophrenic illness itself. The increase in the volume of the lateral ventricles and the area of the anterior horns of the lateral ventricles in the schizophrenic patients was assumed to be related to the schizophrenic pathogenesi