1H Magnetic prefrontal resonance spectroscopy study of dorsolateral cortex in unipolar mood disorder patients

Neuroimaging and postmortem studies have suggested the involvement of the dorsolateral prefrontal cortex (DLPFC) in the pathophysioloy of unipolar disorder. We examined with in vivo H-1 magnetic resonance spectroscopy (MRS) the levels of specific metabolites in the DLPFC of adult unipolar patients and the role of illness chronicity on DLPFC abnormalities. Nineteen unmedicated unipolar mood disorder patients and 19 age- and gender-matched healthy controls underwent a short echo-time H-1 MRS examination localized to an 8-cm(3) single voxel placed in the left DLPFC. There were no significant differences in metabolite levels, including N-acetylaspartate (NAA), phosphocreatine plus creatine (PCr+Cr) and choline-containing-compounds (GPC+PC), between the two groups. However, NAA/PCr+Cr ratios were significantly lower in the chronic than in the less chronically ill patients and healthy controls. The low levels of NAA/PCr+Cr ratios in the left DLPFC of unipolar patients who had been more chronically ill suggest a potential role for illness chronicity in neuronal abnormalities in the DLPFC in unipolar disorder. This could possibly be accounted for by neurodegenerative processes arising with the progression of the illness. Future H-1 MRS investigations should longitudinally examine the role of illness chronicity on DLPFC abnormalities and their relationship with the symptoms of unipolar disorder. (c) 2005 Elsevier Ireland Ltd. All rights reserved.