White matter microstructure in patients with obsessive-compulsive disorder

Background: Previous diffusion tensor imaging (DTI) studies in patients with obsessive-compulsive disorder (OCD) have reported inconsistent findings, and it is not known whether observed findings are related to abnormalities in axonal structure or myelination. Methods: In this DTI study, we investigated fractional anisotropy, as well as axial and radial diffusivity, in 21 patients with OCD and 29 healthy controls. Results: We found decreased fractional anisotropy in the body of the corpus callosum in the OCD group, which was underpinned by increased radial diffusivity. Limitations: The cross-sectional design was the main limitation. Conclusion: Our findings of increased radial diffusivity provide preliminary evidence for abnormal myelination in patients with OCD.