Ogawa S, et al. - The goal of this paper was to gauge the plasma amino acid profile in major depressive disorder (MDD). Variations were determined in several amino acids and related molecules, in the study cohort. The findings revealed consistently decreased methionine and increased glutamate levels in the two sample sets. This, in turn, pointed towards their involvement in MDD. The possible role of amino acids in the pathophysiology of MDD needed additional research.