Sex Differences in the Corpus Callosum in Schizophrenia: A Combined MRI and DTI Study

Abstract

Past research has identified abnormalities in the corpus callosum (CC), a structure that serves as the primary pathway for interhemispheric communication, in patients with schizophrenia, but the existence of sex differences in the CC remains contentious. This thesis is an investigation of CC size and microstructural abnormalities and the presence of sex differences in the structure in people with schizophrenia. Using Magnetic Resonance Imaging (MRI) techniques including volumetric and diffusion tensor methods, the area, volume and fractional anisotropy (FA) of the CC and its 5 constituent segments were measured in a large group of schizophrenia patients (N = 120), consisting of both first-episode and chronic cases, and a control group of age and sex matched healthy individuals (N = 75). Results indicated that the size (both area and volume) of the CC was significantly reduced in patients relative to controls, with chronic patients demonstrating the smallest volumes, followed by first-episode patients and healthy controls. There were no significant differences in CC size between the sexes, nor was the interaction between sex and diagnosis significant. At the same time, CC FAs did not differ significantly between the sexes or between schizophrenia patients and controls. The results suggest that the CC is neither sexually dimorphic in healthy individuals nor in schizophrenia patients. The neurodegenerative hypothesis of schizophrenia is supported as findings suggest that structural abnormalities worsen with illness progression.