Relating depressive and manic symptomatology to 1H-MRS spectra

Abstract

Background: Alterations in neurochemical levels are potential biomarkers of affective disorders and offer a window into illness etiology. Much of the research done to date limits focus to few metabolites and relies on dichotomous diagnoses. Here, using 1H magnetic resonance spectroscopy (MRS), we generate profiles of association between depressive and manic symptom rating scales and numerous metabolites. Methods: MRS data were collected in 30 individuals (7 = major depressive disorder; 5 bipolar disorder and 18 unaffected individuals) in the right anterior cingulate cortex (ACC), insula and hippocampus. All participants were administered mania and depression symptom scales. Results: Small to medium relationships were observed between total choline (tCho), N-acetylaspartate (NAA), myo-inositol (mIns) and depressive and manic symptoms. Associations between NAA and mania (r = –0.47, p = 8.88×10−03) in the hippocampus, and tCho (r = –0.48, p = 8.79×10−03) and NAA (r = –0.44, p = 0.01) and mania in the ACC withstood multiple testing correction. Conclusions: Elevated levels of choline-containing compounds (tCho) and reduced NAA measured in the ACC and hippocampus are associated with mania indexed dimensionally. These metabolites may represent potential in vivo biomarkers for bipolar disorder symptomatology that warrant follow-up.

Keywords

• Depression
• Mania
• Bipolar disorder
• Major depressive disorder
• Mass spectroscopy