The Changes of Gut Microbiota in Drug-Naïve First-Episode MDD Patients Under Treatment by SSRIs

Abstract

Background Recently, gut microbiota has been found to play an important role during the development of MDD in mice models. Meanwhile, the antidepressant treatment with SSRIs could correct the abnormal performance in mice, and played a dual role of antibiotics. Therefore, this study aims to further explore whether the gut microbiota of MDD patients can be reshaped after receiving SSRI drugs.Methods Thirty patients with drug-naive first-episode MDD and thirty healthy controls were recruited and their samples were collected to complete 16S rRNA sequencing. All patients received standardized treatment with ecitalopram. When the reduction rate of HAMD scale score ≥ 50%, their fecal samples were collected again to sequence as follows group. Bioinformatics analysis was used to understand the changes of gut microbiota before and after treatment.Results A significant difference in gut microbiota abundance was found after treatment with escitalopram. The Firmicutes/Bacteroides ratio decreased significantly in the follows group. After treatment, the differences in the classification and metabolic pathways of gut microbiota still existed between follows group and controls. The mainly difference were found as follows: Transport and catabolism, Nervous system, Glycan biosynthesis and metabolism, etc.Conclusions The study found that the gut microbiota of patients with first-episode MDD was similar, but was significantly different from controls. Under escitalopram treatment, the gut microbiota diversity of MDD patients tended to transform to normal. However, there were still some differences of structures and metabolic pathways in microbes between patients and controls, which might be related to the relapse of MDD.