Associations of neurofunctional, morphometric and metabolic abnormalities with clinical symptom severity and recognition deficit in obsessive-compulsive disorder.

Background: Obsessive-compulsive disorder (OCD) causes neural dysfunction associated with cognitive deficit and emotional dysregulation. This study assessed the associations of the neurofunctional changes, gray matter (GM) and white matter (WM) volume alterations in conjunction with in vivo metabolic changes on the working memory tasks in patients with OCD.

Methods: Eighteen patients with OCD and 18 healthy controls matched for age, sex, and educational levels underwent high-resolution T1-weighted magnetic resonance imaging (MRI), event-related functional MRI (fMRI), and proton magnetic resonance spectroscopy (H-MRS) at 3T.

Results: In fMRI, patients with OCD showed lower activities in the cerebellum, inferior temporal gyrus, orbitofrontal gyrus, dorsolateral prefrontal cortex and calcarine gyrus compared to the controls. In VBM, the patients showed significantly reduced GM volumes, especially in the cerebellum, hippocampus, and superior temporal gyrus, together with significantly reduced WM volumes in the retrolenticular part of the internal capsule, dorsolateral prefrontal cortex (DLPFC) and orbitofrontal gyrus. In H-MRS, the ratios of N-acetylaspartate/creatine and choline/creatine were significantly lower in the DLPFC of the patients than in the controls, whereas the ratio of β∙γ-glutamine-glutamate/creatine was significantly higher in the patients than in the controls.

Limitations: This study examined small numbers of subjects in each one of the groups.

Conclusions: The findings will be helpful to aid us in understanding of neurocognitive impairment in OCD, and thus, enhancing the diagnostic accuracy for OCD by additional information on the associated brain functional deficit, cerebral volume change and metabolic abnormality.