Abnormal white matter structural connectivity in adults with obsessive-compulsive disorder

J Gan,Yi Wang,W Liu,J Fan,L Zou,M Zhong,R C K Chan,C Niu,C Tan,Ya Wang,X Zhu,S Cai

doi:10.1038/tp.2017.22

Abstract

Obsessive-compulsive disorder (OCD) is a complex and severe psychiatric disorder whose pathogenesis is not fully understood. Recent studies have shown white matter (WM) alterations in adults with OCD, but the results have been inconsistent. The present study investigated WM structure in OCD patients with the hypothesis that large-scale brain networks may be disrupted in OCD. A total of 24 patients with OCD and 23 healthy controls (HCs) were scanned with diffusion tensor imaging. A tract-based spatial statistics (TBSS) approach was used to detect differences across the whole brain in patients with OCD vs HCs; post hoc fiber tractography was applied to characterize developmental differences between the two groups. Relative to HCs, patients with OCD had lower fractional anisotropy (FA) values in the corpus callosum (CC), left anterior corona radiata (ACR), left superior corona radiata (SCR) and left superior longitudinal fasciculus (SLF), and higher radial diffusivity in the genu and body of CC. Among the TBSS de-projected region of interest results, compared with HCs, patients with OCD showed lower of the mean FA values of fiber bundles passing though the SLF, and shorter lengths of ACR, SCR and CC. In conclusion, this study provides novel evidence of widespread microstructural alterations in OCD and suggests that OCD may involve abnormalities affecting a broader network of regions than commonly believed.

Highlights

Obsessive-compulsive disorder (OCD) is a common mental disorder affecting 2 ~ 3% of the general population internationally.[1]Recurrent, intrusive and distressing thoughts and/or repetitive behaviors are regarded as the core difficulties for patients with OCD;[2] impaired attention and spatial working memory abnormalities are common in OCD patients.[3,4] These clinical features predispose patients to impairments of occupational and social functioning
tract-based spatial statistics (TBSS) analysis revealed that the OCD group exhibited three clusters with significantly lower fractional anisotropy (FA) values than those of the healthy control (HC) group, mainly in the regions of the left superior longitudinal fasciculus (SLF), left anterior corona radiata (ACR), left superior corona radiata (SCR) and corpus callosum (CC)
FA values of fiber bundles passing through the ACR, SCR and CC did not differ between the two groups (FAOCD = 0.59 ± 0.02; FAHC = 0.60 ± 0.02; P = 0.078), but the lengths of these fiber bundles were significantly shorter in the OCD group than in the HC group

Summary

INTRODUCTION

Obsessive-compulsive disorder (OCD) is a common mental disorder affecting 2 ~ 3% of the general population internationally.[1]. Analyses have revealed variable FA values in the anterior cingulate, internal capsule, bilateral semioval center extending to medial frontal WM, subinsular WM and corpus callosum (CC), as well as in. Utilizing TBSS, we examined four diffusivity measures (FA, MD, AD and RD) within major WM pathways to explore whether abnormalities of large-scale brain systems were detectable in the brains of patients with OCD. Using post hoc ROI tractography, we examined anatomical connectivity via association and commissural fibers, which have not been investigated previously. A single-shot echo-planar imaging sequence was applied for

MATERIALS AND METHODS

RESULTS

DISCUSSION