Gut Microbiota and Its Associations With Lifestyle Factors in Bipolar and Major Depressive Disorders: A Preliminary Analysis

Abstract

Introduction: Gut dysbiosis is a potential aetiology of bipolar disorder (BD) and major depressive disorder (MDD), though its links to sleep duration, physical activities, and fibre intake remain poorly understood. Materials and method: A total of 30 faecal samples from BD, MDD, and healthy control (HC) groups, were profiled using the 16s rRNA gene sequencing technique, which their relative abundance results were further correlated with sleep duration, physical activities, and fibre intake via Pearson's correlation coefficient. Results: BD and MDD groups exhibited higher Bacteroidota but lower Firmicutes abundance than HC at the phylum level. In contrast, at the genus level, Bacteroides was most abundant in MDD, Prevotella in BD, and Faecalibacterium in HC. The alpha and beta diversity showed no significant differences across groups. However, the LEfSe analysis identified three taxa at the order level inclusive of Oscillospirales (LDA score: 2.53; p-value: 0.07) and Coriobacteriales (LDA score: 2.19; p-value: 0.03) abundance in HC, while Acidaminococcales (LDA score: 2.16; p-value: 0.07) abundance in MDD. Despite low correlations, sleep duration show two significant associations with the profiled gut microbiota: Parabacteroides (r-value: -0.396; p-value: 0.03) and Alloprevotella (r-value: 0.370; p-value: 0.04). However, associations with fibre intake and physical activities were not significant. Conclusion: These preliminary findings suggest that gut dysbiosis is present in both BD and MDD compared to healthy controls, with potential associations with sleep duration. These results highlight the importance of further validation in future studies to explore the mechanism underlying their relationship and their clinical implications.