Experiencing social exclusion changes gut microbiota composition

Gut microbiota is suggested to regulate the host's mental health via the gut-brain axis. In this study, we investigated the relationship between the microbiome and psychological pain due to social exclusion. Adult individuals with (n = 14) and without (n = 25) social exclusion experience were assessed for the psychological status using self-reported questionnaires: Beck Anxiety Inventory (BAI), Beck Depression Inventory, and the UCLA Loneliness Scale. The gut microbiota was analyzed by 16 S rRNA gene sequencing and bioinformatics. The exclusion group had a 1.70-fold higher total BAI score and 2.16-fold higher levels of anxiety-related physical symptoms (p < 0.05). The gut microbial profiles also differed between the two groups. The exclusion group showed higher probability of having Prevotella-enriched microbiome (odds ratio, 2.29; 95% confidence interval, 1.65-2.75; p < 0.05), a significantly reduced Firmicutes/Bacteroidetes ratio, and decreased abundance of Faecalibacterium spp. (p < 0.05) which was associated with the duration and intensity of social exclusion (p < 0.05). Our results indicate that the psychological pain due to social exclusion is correlated with the gut microbiota composition, suggesting that targeting social exclusion-related microorganisms can be a new approach to solving psychological problems and related social issues.