Corpus callosum deficits in antipsychotic-naïve schizophrenia: evidence for neurodevelopmental pathogenesis

The corpus callosum (CC), the largest inter-hemispheric tract connecting the association cortices, has been shown to be affected in disorders with aberrant neurodevelopment. Previous studies that investigated CC abnormalities in schizophrenia have reported mixed findings potentially due to various confounding factors. In this study, we used magnetic resonance imaging to examine a large sample of antipsychotic-naïve schizophrenia patients (n=66) in comparison with age-, sex-, and handedness-matched (as a group) healthy comparison subjects (n=46). Mid-sagittal areas of CC sub-regions--namely, the genu, body, isthmus and splenium--were measured based on Witelson's method with good inter- and intra-rater reliability. The genu and body of the CC were significantly smaller in schizophrenia patients in comparison to healthy subjects after controlling for the potential confounding effects of age, sex and intracranial area. In male schizophrenia patients, there was a significant positive correlation between the age at onset of psychosis and the area of the genu. Together, these findings suggest neurodevelopmentally mediated hypoconnectivity in schizophrenia.