Comparison of Resting-State Spontaneous Brain Activity between Treatment-Naive Patients with Schizophrenia and Obsessive-Compulsive Disorder

Background: Schizophrenia (SZ) and Obsessive-compulsive disorder (OCD) share many demographic and clinical symptoms, genetic risk factors, pathophysiological underpinnings, and brain structure and function. However, the differences in the spontaneous brain activity patterns between the two diseases remain unclear. Here this study aimed to compare the features of intrinsic brain activity in treatment-naive patients with schizophrenia (SZ) and obsessive-compulsive disorder (OCD) and to explore the relationship between spontaneous brain activity and the severity of symptoms. Methods: Twenty-two treatment-naive patients with SZ, twenty-seven treatment-naive patients with OCD, and sixty healthy controls underwent resting-state functional magnetic resonance imaging (fMRI). The amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo) and degree of centrality (DC) of SZ group, OCD group and healthy control (HC) group were compared. Results: Compared with SZ group and HC group, patients with OCD had significantly higher ALFF in the right angular gyrus and the left middle frontal gyrus/precentral gyrus, and significantly lower ALFF in the left superior temporal gyrus/insula/rolandic operculum and the left postcentral gyrus. Compared with HC group, lower ALFF values in the right supramarginal gyrus/inferior parietal lobule and DC values of the right lingual gyrus/calcarine fissure and surrounding cortex of the two patient groups, higher ReHo values in OCD group and lower ReHo values in SZ group in the right angular gyrus/middle occipital gyrus brain region, and higher DC values in the right inferior parietal lobule/angular gyrus in SZ group were documented in the present study. In addition, the ALFF values of the left postcentral gyrus were positively correlated with positive subscale score and general psychopathology subscale score respectively on the Positive and Negative Syndrome Scale (PANSS) in SZ group. The ALFF values in the left superior temporal gyrus/insula/rolandic operculum of patients with OCD were positively correlated with compulsion subscale score and total score respectively on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Conclusion: Our data showed various patterns of spontaneous brain activity damage in resting-state between treatment-naive patients with SZ and OCD, which might imply different underlying neurobiological mechanisms in SZ and OCD.