129. Sex differences in the corpus callosum of chronically ill schizophrenic patients

Abstract

There has been disagreement on whether the corpus callosum (CC) differs between the sexes in either normals or schizophrenic patients. As the major connecting group of fibers between the cerebral hemispheres, the corpus callosum may serve an important functional role in both the symptoms and cognition of schizophrenic patients. Consistent with a meta-analysis by Woodruff et al. (1995), we (Hoff, et al., 1994) found evidence for a reduction in CC area in a group of first episode schizophrenic patients compared to controls, but only in females. In the present study, we used mid-sagittal slices (5 mm, 2.5 mm skip); we measured total CC area and subdivided the CC into five equal segments. Inter-rater reliabilities for total CC area and segments CC 1 (anterior) to CC5 (posterior) were > .99. Seventy-five (56 males, 19 females) DSM-III-R diagnosed chronically ill schizophrenic patients were compared to 75 controls (57 males, 18 females) by within-sex patient versus control comparisons. Results revealed that male patients had statistically significantly smaller total CC area and smaller middle segments (CC2, CC3, CC4) than male controls, but female patients were not significantly different from female controls on any CC measurement. We conclude that in this severely ill group of chronic patients, male patients show CC area reduction but female patients do not. Possible explanations for the observed sex differences will be discussed.