H-1 MRS of hippocampus in bipolar disorder after recovery from the first episode of mania

Abstract

Background: Although it has been extensively investigated, the pathophysiology of bipolar disorder remains unclear. The investigation of stable patients at disease onset is a strategy to avoid the confounding effect of progression of disease, mood state or duration of treatment. Our purpose is to investigate in vivo neuronal metabolites in the hippocampus using Proton Magnetic Resonance Spectroscopy (1H-MRS) after patients have recovered from their first manic episode. Methods: Fifty-eight BD I patients meeting DSM-IV criteria recently recovered from their first episode of mania and 27 healthy subjects were studied using 1H-MRS with a 3.0 T Philips Achieva unit. Voxels with 30X15X15 mm were placed in the hippocampus on both sides of the brain and the signal was collected using a PRESS sequence with TE = 35ms and TR = 2000ms. Data analysis was performed using the LC Model software. Results: N- Acetyl-Aspartate, Choline, Myo-Inositol, Creatine and Glx levels were compared between the groups and no statistically significant difference was found between them. The investigation of psychosis, years of disease, presence of previous depression before mania, duration of manic phase, presence of symptoms and use of medication did not show any difference between the groups. There were no significant associations between all the metabolites, demographic and clinical variables. Conclusion: Our results suggest that at the onset of BD there are no alterations in cell vulnerability or metabolism in the hippocampus after patients have recovered from their first manic episode.