Recent technical developments have made it feasible to comprehensively
assess brain anatomy in psychiatric populations.
To describe the structural brain alterations detected in the magnetic
resonance images of a large series of patients with obsessive-compulsive disorder
(OCD) using imaging procedures that allow the evaluation of volume changes
throughout the brain.
Referral OCD unit in a tertiary hospital.
A consecutive sample of 72 outpatients with OCD and 72 age- and sex-matched
Three-dimensional sequences were obtained in all participants. A statistical
parametric mapping approach was used to delineate possible anatomical alterations
in the entire brain. To preserve volumetric information, voxel values were
modulated by the Jacobian determinants (volume change measurement) derived
from spatial normalization.
Main Outcome Measures
Voxelwise brain volumes.
The brains of patients with OCD showed reduced gray matter volume in
the medial frontal gyrus, the medial orbitofrontal cortex, and the left insulo-opercular
region. A relative increase in gray matter volume was observed bilaterally
in the ventral part of the putamen and in the anterior cerebellum. All these
brain alterations were abnormally correlated in patients with OCD, and age
statistically significantly contributed to the relative enlargement observed
in the striatal areas. Disease severity, the nature of symptoms, and comorbidities
were not related to the changes described. Nevertheless, patients with prominent
aggressive obsessions and checking compulsions showed reduced amygdala volume
in the right hemisphere.
The pattern of anatomical features depicted by this voxelwise approach
is consistent with data from functional studies. The reported anatomical maps
identified the specific parts of the frontostriatal system that were altered
in patients with OCD and detected changes in anatomically connected distant
regions. These data further define the structural brain alterations in OCD
and may contribute to constraining the prevailing biological models of this