Sex-specific brain morphometric associations with psychopathology severity in obsessive-compulsive disorder

Female patients with obsessive-compulsive disorder (OCD) exhibit more severe psychopathological symptoms, yet their underlying neural correlates remain unclear. This study aimed to determine OCD-specific sex differences in brain structure and examine whether these differences are associated with the greater psychopathological burden observed in female patients.

Structural MRI data and symptom severity assessments were obtained from 147 unmedicated OCD patients (69 females) and 98 demographically matched healthy controls (HC; 46 females).

Female patients with OCD showed significantly higher levels of OCD symptom severity, depression and anxiety symptoms than male patients. A significant interaction effect between group and sex on cortical complexity in the right paracentral lobule was identified, indicating that sex differences in this brain region differed significantly between OCD and HC groups. More specifically, female patients with OCD showed lower cortical complexity in the right paracentral lobule than male patients, whereas in the HC group, females exhibited higher cortical complexity than males. In the OCD group, lower cortical complexity was related to greater depression and anxiety symptoms and showed an indirect serial association with OCD symptom severity via anxiety.

This study identified an OCD-specific brain morphometric basis of sex differences and suggested a potential pathway through which morphometric features in this region may be associated with greater OCD symptom severity in females via anxiety.