AIM: In the present study, we aimed to determine the volume differences in brain regions involved in cortical-striatal-thalamic-cortical circuit (CSTC) between healthy subjects and obsessive–compulsive disorder (OCD) patients. We also evaluated the potential relationship between volumes of region of interest and various illness parameters (duration and current severity OCD, and the influence of drug treatment).
METHODS: We examined the volumetric differences in dorsolateral prefrontal cortex (DPFC), orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), thalamus and striatum between OCD patients (n = 21) and healthy controls (HCs) (n = 25).
RESULTS: Patients with OCD had significantly larger total, right, and left DLPFC, and OFC volumes compared to HCs. Total, and left ACC, total, and left striatum volumes were significantly smaller in OCD patients than in HC. The thalamus volumes were not different between two groups. The most of volumetric correlations in HCs disappeared among OCD patients. Only, the correlation between the volumes of left striaum and left ACC volume remained significant. Fisher’s r-to-z transformation tests indicated that correlation coefficients of brain volumes significantly differed between both groups for right ACC and left (z = 2.17, p = .03) and right OFC (z = 2.00, p = .04); left ACC and right OFC (z = 2.41, p = .01); right ACC and left (z = 2.94, p = .003), and right striatum (z = 2.43, p = .01).
CONCLUSIONS: Our findings indicate the impaired connectivity of ACC, OFC, and striatum in the pathophysiology of OCD. Further research is needed to explore precisely which brain regions nuclei are specifically involved in the occurence of OCD symptoms.