Evidence to suggest that OCD is a brain illesss

Using the same methods as have been used to show schizophrenia reduces
brain volume in children OCD too has been shown to do the same. I
haven't read the study by the abstract of this MRI paper seems to
indicate the existence of different patterns of brain development,
patterns which the researcher considers pathological.

Corpus callosal morphology in treatment-naive pediatric obsessive
compulsive disorder.
http://www.ncbi.nlm.nih.gov/pubmed/9460091

"
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.
"