Corpus callosal morphology in treatment-naive pediatric obsessive compulsive disorder

1. Abnormalities in association circuits have been described in Obsessive Compulsive Disorder (OCD) and may reflect neurodevelopmental abnormalities. Primary and association cortices are topographically mapped in the corpus callosum (CC). The authors hypothesized alterations in CC subdivisions that connect association, but not primary cortices in pediatric OCD. The authors predicted that normal age-related increases in CC area would be absent in OCD. 2. The authors compared the midsagittal magnetic resonance images of 21 psychotropic-naive, nondepressed OCD patients, 7.2-17.7 years, and 21 case-matched healthy controls. Total CC area as well as that of the anterior, middle and posterior genu, anterior and posterior bodies, isthmus, and the anterior, middle and the posterior splenii were measured. 3. All of the CC regions except the isthmus were significantly larger in OCD patients than in controls. CC area correlated significantly with OCD symptom severity but not illness duration. The age-related increase in CC size seen in normal subjects was absent in OCD patients. 4. These findings support theories of abnormal association cortex development in OCD but also suggest possible abnormalities of other primary cortical regions as well.