Proton magnetic resonance spectroscopy (1H MRS) in schizophrenia:: Investigation of the right and left hippocampus, thalamus, and prefrontal cortex

Single voxel proton magnetic resonance spectroscopy (H-1 MRS) was used to study the metabolites N-acetyl-aspartate (NAA), choline (CHO), and myo-inositol (mI) in order to test a neurodegenerative hypothesis in schizophrenia (decrease of NAA, increase of CHO, and increase of mI) and a cerebral asymmetry of these metabolites. H-1 MRS was performed in 17 schizophrenia patients and 14 healthy subjects in three cerebral areas highly involved in the pathophysiology of schizophrenia (the prefrontal cortex, the thalamus, and the hippocampus). The ratio amplitudes between metabolites and creatine plus phosphocreatine (Cr) were determined. No difference in the metabolites existed between patients and healthy subjects. However, relationships were noted between NAA/Cr and age in the thalami of the schizophrenia patients (r = -0.37; p = 0.14) and healthy subjects (r = 4.52; p = 0.05). A significant correlation was observed between NAA/Cr and age of onset of illness in the hippocampi of schizophrenia patients (r = -0.59; p < 0.05). Moreover, NAA/Cr was lower in the right than in the left prefrontal cortex in both schizophrenia patients and healthy subjects. There was no relationship between the metabolites and duration of illness or dose of antipsychotics. These findings might suggest a neurodegenerative process in the hippocampi of schizophrenia patients with late onset of illness, and the NAA/Cr ratio could be a marker of aging in the thalami.