Hemispheric asymmetries on computed tomographic scans in schizophrenia and mania. A controlled study and a critical review.

A major reason for reassessing hemispheric asymmetries in schizophrenics by computed tomography is the methodologic shortcomings of previously published measurement techniques. We used completely blind measurements, multiple measurements performed by two independent examiners of each region of the brain, and an SE of measurement with a confidence level of P less than .01 to define significant asymmetry. The frequency of reversed occipital asymmetry was significantly higher in the 36 schizophrenic than in the 18 manic right-handed male patients. Furthermore, when all of the previously published techniques were applied to these patients, the frequency of such a reversal was consistently higher in the schizophrenic than in the manic group. Further investigation of hemispheric asymmetries in schizophrenics is warranted.