Analyzing the Monosodium and Dietary Glutamate Model of Depression: A Narrative Review

Background: This narrative review aimed to explore the scientific understanding of the role of monosodium glutamate and dietary glutamate in depressive-like phenotypes. It illuminated the findings that are linked to the monosodium glutamate (MSG) model of depression, curating recent literature on MSG-induced depression and the closely related sphere of MSG induced neurotoxicity. Methodology: A comprehensive search of the literature from 2010 to 2025 was conducted using Google Scholar, PubMed, and Scopus databases, focusing on peer-reviewed studies with definite outcomes. A narrative review was done due to the limited number of eligible studies. Results: A comprehensive search of relevant databases having studies of MSG induced neurobehavioral and pathophysiological changes in depression was conducted with preference for recency of studies (up to two decades back). Supraphysiological doses and/or the parenteral route of monosodium glutamate can consistently induce depressive-like phenotypes in animal models. The limitations of the MSG model of depressive-like behavior were also critically analyzed. Three thousand five hundred and eighty results came from the searches, with sixty-three studies adjudged to meet the inclusion criteria. Conclusion: The monosodium glutamate model of depression provides a valuable approach to understanding the multifaceted nature of depression. Future endeavors should focus on the standardization of methodological processes and the incorporation of the evaluation of the chronic effects of monosodium glutamate in human studies.