Insular volumes in first-episode schizophrenia: gender effect

Insula is a multimodal sensory integration region that acts as a gateway between somatosensory areas and limbic structures such as amygdala. Only a handful of region of interest (ROI) studies have suggested insular volume reduction in patients with schizophrenia but none have documented a gender effect on the volume of this structure. The authors used magnetic resonance images to measure insular volumes in previously untreated patients with first-episode schizophrenia (N=30) relative to those of healthy comparison subjects (N=30). Correlations with symptom severity were carried out. Intracranial volume was used as a covariate in the analysis. Female patients (N=15) had significantly reduced right insular volume relative to healthy female comparison subjects (p<0.05). On preliminary analysis, the right and left insular volumes in female patients had significant negative correlations with the positive symptoms scores (p<0.05), but not on correcting for multiple comparisons. Insula is developmentally and phylogenetically a watershed region where the more primitive allocortex transitions into the more developed isocortex. Thus its role as a substrate of neurodevelopmental hypothesis in schizophrenia and the interplay with gender deserves more attention.