The relationship of occipital skull asymmetry to brain parenchymal measures in schizophrenia.

It has long been hypothesized, but never proven that an organic brain injury early in life predisposes to schizophrenia. Since brain and cranial development are closely linked, if such an event occurred early enough in the premorbid course of schizophrenia, it could conceivably effect skull architecture. To approach this question, the occipital bone depth and the occipitomedian angle were measured in 50 patients with chronic schizophrenia and in 35 medical controls. Strong correlations emerged between the skull asymmetry indices and the occipital and temporal lobe parenchymal asymmetry indices. There were no statistically significant differences in cranial asymmetry measures between the patients with schizophrenia and the medical controls. However, when the comparison was limited to right handed individuals with homolateral sighting dominance, a weak, but statistically significant trend was observed for more symmetrical slanting along the sagittal suture in the schizophrenic patients. In addition, cranial asymmetry was weakly predictive of increased prefrontal markings in the schizophrenic patients. The congruence of skull findings with parenchymal variables suggests that certain aspects of skull and parenchymal architecture are co-determined.