Corpus callosum in patients with obsessive-compulsive disorder: diffusion-tensor imaging study

To prospectively examine microstructural white matter abnormalities in the corpus callosum (CC) of patients with obsessive-compulsive disorder (OCD), as compared with control subjects, and to investigate the relationship between diffusion-tensor (DT) imaging measures of the CC region and clinical symptoms of OCD.

Institutional review board approval was obtained, and each participant--or the participant's parent(s)--provided written informed consent. Sixteen patients with OCD (seven male, nine female; mean age, 28.7 years +/- 9.8 [standard deviation]) and 16 matched healthy volunteers (control subjects) (seven male, nine female; mean age, 29.9 years +/- 9.0) were examined. Mean diffusivity and fractional anisotropy (FA) were measured in five subdivisions of the CC. The paired t test was performed to compare the mean diffusivity or the FA in CC regions between the patients with OCD and the control subjects.

There were no significant differences (rostrum, P = .15; genu, P = .88; rostral body, P = .12; isthmus, P = .77; splenium, P = .88) in mean diffusivity between the patients with OCD and the healthy volunteers. A significant reduction in FA was observed in the rostrum of the CC in patients with OCD compared with the rostral FA in the control subjects (P < .001). Higher FA in only the rostrum correlated significantly with lower Yale-Brown obsessive-compulsive scale score (r = -0.72, P = .002).

Study results support the widely held view that the orbital prefrontal region is involved in the pathophysiology of OCD and indicate that the orbitofrontal circuit influences symptom severity in patients with OCD.