Background: Current hypotheses about the neuroanatomical structures involved in obsessive-compulsive disorder (OCD) suggest abnormalities in cortical-striatal-thalamic-cortical circuits. This study examined selected brain regions within or adjacent to these circuits.
Methods: Magnetic resonance imaging scans from 26 patients with OCD and 26 healthy controls were analyzed to determine the volumes of the following structures: prefrontal cortex (cortex anterior to the genu of the corpus callosum), caudate nucleus, lateral and third ventricles, and whole brain.
Results: Patients with OCD had significantly smaller caudate nucleus volumes than controls (F[1,48] = 9.4, P = .004) but did not differ in prefrontal cortex size or in volumes of the lateral or third ventricles. Structural volumes were not significantly correlated with the duration or severity of OCD symptoms.
Conclusion: Our findings provide additional evidence for pathological involvement of the caudate in OCD.