No change in N-acetyl aspartate in first episode of moderate depression after antidepressant treatment: 1H magnetic spectroscopy study of left amygdala and left dorsolateral prefrontal cortex

Abstract

BackgroundThe role of brain metabolites as biological correlates of the intensity, symptoms, and course of major depression has not been determined. It has also been inconclusive whether the change in brain metabolites, measured with proton magnetic spectroscopy, could be correlated with the treatment outcome.MethodsProton magnetic spectroscopy was performed in 29 participants with a first episode of moderate depression occurring in the left dorsolateral prefrontal cortex and left amygdala at baseline and after 8 weeks of antidepressant treatment with escitalopram. The Montgomery-Asberg Depression Rating Scale, the Hamilton Rating Scale for Depression, and the Beck Depression Inventory were used to assess the intensity of depression at baseline and at the endpoint of the study. At endpoint, the participants were identified as responders (n=17) or nonresponders (n=12) to the antidepressant therapy.ResultsThere was no significant change in the N-acetyl aspartate/creatine ratio (NAA/Cr) after treatment with antidepressant medication. The baseline and endpoint NAA/Cr ratios were not significantly different between the responder and nonresponder groups. The correlation between NAA/Cr and changes in the scores of clinical scales were not significant in either group.ConclusionThis study could not confirm any significant changes in NAA after antidepressant treatment in the first episode of moderate depression, or in regard to therapy response in the left dorsolateral prefrontal cortex or left amygdala. Further research is necessary to conclude whether NAA alterations in the first episode of depression could possibly be different from chronic or late-onset depression, and whether NAA alterations in stress-induced (reactive) depression are different from endogenous depression. The potential role of NAA as a biomarker of a treatment effect has yet to be established.

Choline elevation in amygdala region at recovery indicates longer survival without depressive episode: a magnetic resonance spectroscopy study

“…We previously reported no NAA changes in the left amygdala before and after an 8-week long AD treatment (Janović et al 2014 ). Michael et al ( 2003 ) analyzed MRS changes in the amygdala of treatment-resistant MDD patients and found a significant increase in NAA in ECT monotherapy responders, as well as after ECT was combined with AD therapy in non-responders.…”

Promising Neuroimaging Biomarkers in Depression

“…However, some studies were still against the significant roles of fronto-limbic regions as biomarkers of MDD. A MRS study showed that N-acetyl aspartate levels showed no significant changes in the DLPFC and amygdala of first-episode MDD patients after antidepressant treatment [70]. A meta-analysis showed a lack of increases in the brain-derived neurotrophic factor after non-invasive brain stimulation in the DLPFC of MDD patients [71].…”