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.