Structural brain abnormalities correlate with clinical features in patients with drug-naïve OCD: A DARTEL-enhanced voxel-based morphometry study.

BACKGROUND: Abnormal brain structure has been reported in obsessive-compulsive disorder (OCD), but findings from these reports have been inconsistent. This study aimed to gain more detailed insights into gray matter structure and correlate this structure with clinical features in patients with drug-naïve OCD using voxel-based morphometry (VBM).

METHODS: Voxel-based morphometry and tools of Diffeomorphic Anatomical Registration through Exponentiated Lie Algebra (DARTEL) were used to investigate structural differences in gray matter volume between 26 drug-naïve OCD patients and 32 healthy controls. Partial correlation analysis was used to analyze associations of gray matter abnormalities with Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores and illness duration.

RESULTS: Compared to healthy controls, drug-naïve OCD patients showed significantly smaller gray matter volume in the right dorsolateral prefrontal cortex (DLPFC), left superior temporal gyrus, left precuneus and right precentral gyrus, as well as significantly greater gray matter volume in the left anterior insula and right parahippocampal gyrus (p<0.05, corrected using the familywise error rate). Y-BOCS scores correlated positively with gray matter volume in the left anterior insula, while they correlated negatively with gray matter volume in the right DLPFC.

CONCLUSIONS: OCD pathophysiology may involve structural changes in the DLPFC-parietal regions, including the dorsolateral prefrontal cortex, precuneus, superior temporal gyrus and connected limbic structures such as the parahippocampal gyrus and anterior insula. Longitudinal studies are needed that integrate anatomical, functional and diffusion MRI data.