Association between major depressive disorder and gut microbiota dysbiosis

Objective Major depressive disorder (MDD) affects 300 million people globally, with dysbiosis altering the central nervous system potentially having a role in this disorder. Dysbiosis is characterized by a decrease in microbial diversity and an increase in proinflammatory species. The human gut microbiota refers to the trillions of microbes, such as bacteria, that live in the human gut. The purpose of this study was to compare the gut microbiota of patients with MDD with healthy controls. Methods This case-control study involved 35 MDD cases and 35 healthy age- and sex-matched controls. Stool samples were collected and subjected to quantitative real-time PCR. Four intestinal bacterial phyla (firmicutes, bacteroidetes, actinobacteria, and proteobacteria) were investigated by 16SrRNA analysis. Results The relative abundance of bacteroidetes to firmicutes in the control and case groups was .66 and 1.33, respectively ( P < .05). There were no significant differences in actinobacteria and proteobacteria among those in the MDD group compared to the healthy control group. Conclusions Gut microbiota dysbiosis may significantly contribute to the onset of depression, underscoring the importance of understanding the relationship between MDD and gut microbiota. Firmicutes, which produce short-chain fatty acids, are crucial for intestinal health. However, dysbiosis can disrupt the gut microbiota, contributing to depression and impacting the central nervous system.