"Comparison of parietal cortex volumes in schizophrenia and schizoaffective disorder"

Schizophrenia and schizoaffective disorder are closely related psychotic disorders with overlapping clinical features and unclear neurobiological boundaries. In our study, we aimed to compare bilateral parietal cortex volumes among patients diagnosed with schizophrenia, patients diagnosed with schizoaffective disorder, and a healthy control group, and to examine their relationship with clinical characteristics. Bilateral parietal lobe volumes were obtained using the Brain Segmentation and Parcelation Method (BPM) for 20 patients diagnosed with schizophrenia, 24 patients diagnosed with schizoaffective disorder, and 21 healthy controls, and intergroup comparisons were made. The severity of clinical symptoms was assessed using the Schizophrenia Negative Symptom Scale (SANS) and the Schizophrenia Positive Symptom Scale (SAPS). Both the schizophrenia and schizoaffective disorder groups showed a decrease in parietal cortex volume compared to the healthy control group. No significant volumetric differences were observed between the two patient groups. Schizophrenia patients showed significantly higher negative symptom severity compared to schizoaffective disorder patients. These findings indicate that parietal cortex abnormalities are common across the psychosis spectrum and support dimensional models of psychotic disorders.