White matter abnormalities in children and adolescents with obsessive-compulsive disorder: a diffusion tensor imaging study.

BACKGROUND: There is paucity of data on white matter (WM) abnormalities in juvenile obsessive-compulsive disorder (OCD). This study aimed to identify WM microstructure changes in juvenile OCD.

METHODS: Fifteen children and adolescents with OCD and 15 matched healthy controls underwent diffusion tensor imaging using a 3 Tesla (Achieva, Best, The Netherlands) magnetic resonance imaging scanner. Voxelwise analyses were conducted on data processed through tract-based spatial statistics (TBSS).

RESULTS: Patients significantly differed from controls in axial as well as radial diffusivities, but not in fractional anisotropy. Patients demonstrated significantly increased axial diffusivity in corpus callosum (genu, body, and splenium), right and left superior longitudinal fasciculi, left inferior longitudinal fasciculus, right and left cingulum, bilateral anterior thalamic radiations, bilateral anterior limb of internal capsule, left posterior limb of the internal capsule, and middle cerebellar peduncle. In addition, significantly increased radial diffusivity was seen in patients in genu of the corpus, right and left superior longitudinal fasciculi, left inferior longitudinal fasciculus, right and left uncinate fasciculi, bilateral anterior thalamic radiation, bilateral inferior fronto-occipital fasciculus, left posterior limb of internal capsule, right superior cerebellar peduncle, middle cerebellar peduncle, and right inferior cerebellar peduncle.

CONCLUSIONS: Our findings suggest involvement of multiple WM tracts in juvenile OCD. In addition to the widely proposed hypothesis of orbitofrontal-striato-thalamo-cortical circuitry deficits in the development of OCD, our findings suggest involvement of additional brain regions, possibly parietal cortex, lateral prefrontal cortex, and limbic system. The widespread differences in WM among cases and controls also points to the possibility of underlying myelination changes.