Neurochemical abnormalities detected by proton magnetic resonance spectroscopy in patients with obsessive-compulsive disorder

Abstract

Objective To study the neurochemistry of insular lobe in patients with obsessivecompulsive disorder. Methods Seventeen unmedicated male patients with obsessive-compulsive disorder and 17 healthy controls were scanned by multi voxel proton magnetic resonance spectroscopy (1H-MRS) to measure the levels of N-acetylaspartate (NAA),choline (Cho),glutamate/glutamine (Glx) and creatine (Cr) in insular lobe.The levels of the 1 H-MRS metabolites in insular lobe between patients and healthy controls were compared.The associations between the metabolite levels and symptom severity were examined. Results NAA/Cr levels from bilateral insular lobe were significantly lower in patients than in controls[for left,(1.54±0.16) vs. (1.66±0.14),t=-2.298,P=0.028; for right,(1.58±0.14) vs. (1.68±0.14),t=-2.129,P=0.041].The bilateral NAA/Cr levels were negatively related to the symptom severity (for left,r=-0.536,P=0.027; for right,r=-0.663,P=0.004).Cho/Cr levels from bilateral insular lobe were significantly higher in patients than controls[for left,(1.07±0.14) vs. (0.89±0.12),t=4.169,P=0.000; for right,(1.12±0.12) vs. (0.96±0.13),t=3.565,P=0.000].The bilateral Cho/ Cr levels were positively related to the symptom severity (for left,r=0.737,P=0.001; for right,r=0.686,P=0.002).No significant differences were found in Glx/Cr levels between the patients and controls (for left,r=-0.177,P=0.496;for right,r=0.214,P=0.411). Conclusions The findings suggest that the changes in the levels of NAA and Cho in insular lobe may be implicated in the pathogenesis of obsessive-compulsive disorder. Key words: Obsessive-compulsive disorder; Magnetic resonance spectroscopy; Insular lobe