Glutamatergic abnormalities in the pregenual anterior cingulate cortex in obsessive-compulsive disorder using magnetic resonance spectroscopy: A controlled study

•OCD is connected with abnormalities in the pgACC, which is a part of the CSTC.•We describe disruption of the Glu, Gln, Glx, and GABA metabolism in the pgACC.•A decrease in Glx, Glu, and Gln was observed in the pgACC in OCD.•In OCD we observed positive correlation of Glu and the severity of compulsions. In this study, we utilized proton magnetic resonance spectroscopy (MRS) to understand the role of glutamate (Glu), glutamine (Gln), and gamma-aminobutyric acid (GABA) of OCD patients in the pregenual anterior cingulate cortex (pgACC). In total, 54 patients with OCD and 54 healthy controls (HC) matched for age and sex were included in the study. They underwent MRS in the pgACC region to calculate the concentrations of Glu, Gln, GABA, and Glu + Gln (Glx). After quality control of the MRS data, 21 OCD and 21 HC were statistically analyzed. The severity of symptoms were evaluated using the Yale–Brown Obsessive-Compulsive Scale (YBOCS). In the statistical analysis, we compared differences between groups for the metabolites; in the OCD we analyzed the correlations with symptom severity, medication status, age, and duration of illness. A significant decrease in Glx, in Glu, and in Gln in the pgACC were observed in the OCD compared to HC. The correlation statistics showed a significant positive correlation between Glu levels and the YBOCS compulsions subscale. The results indicate that patients with OCD present a disturbance in glutamatergic metabolism in the pgACC. The results also demonstrate that these changes correlate with the severity of compulsions.