First Rank Symptoms (FRS) - a group of intriguing experiences characterized by striking breach of ‘self versus non-self’ boundaries - have had a critical influence on the diagnosis of schizophrenia. Inferior Parietal Lobule is implicated in the pathogenesis of FRS in Schizophrenia. However, the role of Planum Parietale (PP) in the genesis of FRS is yet to be examined.

This first time study (to the best of our knowledge), aims to examine antipsychotic-naïve schizophrenia patients for the effect of FRS status on volume of PP.

In this study we examined the volume of PP in antipsychotic-naïve schizophrenia patients (n = 32; M:F = 16:16) in comparison with age, sex, and handedness matched (as a group) healthy comparison subjects (n = 34; M:F = 16:18) using valid method with good inter-rater reliability.

Female Schizophrenia patients showed significant volume reduction in right PP in comparison with female healthy controls (F = 7.2; p = 0.01). However, male patients did not. There was a significant effect of schneiderian FRS in female patients in that those who had FRS had significantly smaller volume of right PP than healthy controls (F = 3.8; p = 0.03); where those female patients who were FRS negative did not differ. Left PP volume did not differ between patients and controls.

Current study supports previous studies which have implicated the role of parietal lobe in pathogenesis of FRS. Specific role of PP in FRS generation and possible implication of sex differences needs further systematic studies.