Frontal white matter biochemical abnormalities in first-episode, treatment-naive patients with major depressive disorder: A proton magnetic resonance spectroscopy study

Background: Previous neuroimaging studies found evidence of brain functional and structural abnormalities in patients with major depressive disorder (MOD), but they rarely excluded compounding effects of some important factors, such as medication and brain degeneration. This study sought to explore the brain biochemical changes of first-episode, treatment-naive, non-late-life adult patients with MOD in the frontal white matter and gray matter by using proton magnetic resonance spectroscopy (H-1 MRS). Methods: Twenty-four first-episode, treatment-naive, non-late-life adult depressed patients and 13 healthy controls were enrolled in this study. Subjects underwent two-dimensional mulfivoxel H-1 MRS at 1.51 to obtain bilateral metabolite levels from the dorsolateral prefrontal white matter and anterior cingulate gray matter. Results: Patients with MOD showed significantly lower N-acetylaspartate/creatine (NAA/Cr) and choline/creatine (Cho/Cr) ratios in the left dorsolateral prefrontal white matter, and lower NM/Cr ratios in the right dorsolateral prefrontal white matter when compared with the control subjects. There were no significant differences in the metabolite ratios in the bilateral anterior cingulate gray matter. Conclusions: These findings suggest that biochemical abnormalities in prefrontal white matter may occur early in the course of MOD and may be related to the neuropathology of depression. (C) 2011 Elsevier B.V. All rights reserved.