Decreased Functional Connectivity of Insular Cortex in Drug Naive First Episode Schizophrenia: In Relation to Symptom Severity

Background This study was to examine the insular cortical functional connectivity in drug naive patients with first episode schizophrenia and to explore the relationship between the connectivity and the severity of clinical symptoms. Methods Thirty-seven drug naive patients with schizophrenia and 25 healthy controls were enrolled in this study. A seed-based approach was used to analyze the resting-state functional imaging data. Insular cortical connectivity maps were bilaterally extracted for group comparison and validated by voxel-based morphometry (VBM) analysis. Clinical symptoms were measured using the Positive and Negative Syndrome Scale (PANSS). Results There were significant reductions in the right insular cortical connectivity with the Heschl's gyrus, anterior cingulate cortex (ACC), and caudate (p's<0.001) in the patient group compared with the healthy control (HC) group. Reduced right insular cortical connectivity with the Heschl's gyrus was further confirmed in the VBM analysis (FDR corrected p<0.05). Within the patient group, there was a significant positive relationship between the right insula-Heschl's connectivity and PANSS general psychopathology scores (r = 0.384, p = 0.019). Conclusion Reduced insula-Heschl's functional connectivity is present in drug naive patients with first episode schizophrenia, which might be related to the manifestation of clinical symptoms.