Strain-level structure of gut microbiome showed potential association with cognitive function in major depressive disorder: A pilot study.

BACKGROUND: Although the association between gut microbiota and the pathogenesis of major depressive disorder (MDD) has been well studied, it is unclear whether gut microbiota affects cognitive function in patients with MDD. In this study, we explored the association between gut microbiota and cognitive function in MDD and its possible mechanisms. METHODS: We enrolled 57 patients with MDD and 30 healthy controls (HCs) and used 16S rRNA gene sequencing analysis and shotgun metagenomic sequencing analysis to determine gut microbial composition. RESULTS: The richness and diversity of gut microbiota in patients with MDD were the same as those in HCs, but there were differences in the abundance of Bifidobacterium and Blautia. Compared with HCs, two strains (bin_32 and bin_55) were significantly increased, and one strain (bin_31) was significantly decreased in patients with MDD based on the strain-level meta-analysis. Time to complete the Stroop-C had significant negative correlations with bin_31 and bin_32. Bin_55 had significant negative correlations with time to complete the Stroop-C, time to complete the Stroop-CW, and repeated animal words in 60 s but significant positive correlations with correct answers in 120 s on the Stroop-CW. LIMITATIONS: This study only tested the cognitive function of MDD in a small sample, which may have caused some bias. CONCLUSIONS: Based on our strain-level analysis, we found that gut microbiota may be associated with the pathogenesis of MDD and may have potential effects on cognitive function.