Association of Alterations in Intestinal Microbiota With Impaired Psychological Function in Patients With Inflammatory Bowel Diseases in Remission

BACKGROUND & AIMS: Depression and anxiety are frequent comorbidities with inflammatory bowel diseases (IBD). Alterations to the intestinal microbiome promote not only intestinal inflammation but also psychologic function. We studied the interactions between the composition of the intestinal microbiota and psychological outcomes in patients with IBD in Switzerland. METHODS: We performed a prospective study of psychological comorbidities and quality of life (QoL) in 171 participants in the Swiss IBD Cohort Study with IBD in remission. Participants complete the Hospital Anxiety and Depression Scale, Perceived Stress Questionnaire, the 36-Item Short Form Survey, and the IBD QoL Questionnaire. Microbes were collected from intestinal biopsies and analyzed by 16S rRNA high-throughput sequencing. RESULTS: Microbiomes of patients with higher perceived stress had significantly lower alpha diversity. Anxiety and depressive symptoms were significantly associated with beta diversity. We found a negative correlation between psychological distress and abundance of Clostridia, Bacilli, Bacteroidia, and Beta- and Gamma-proteobacteria. Psychological distress was also associated with decreases in operational taxonomic units from the lineages of Lachnospiraceae, Fusobacteriaceae, Ruminococcaceae, Veillonellaceae, Alcaligenaceae, Desulfovibrionaceae, and Bacteroidaceae families. The relative abundance of Bifidobacterium in patients with Crohn's disease and Desulfovibrio in patients with ulcerative colitis correlated with depression, whereas abundance of Sutterella, RF 32, and Lactococcus correlated with quality of life in patients with Crohn's disease. CONCLUSIONS: We identified correlations between the composition of the intestinal microbiota in patients with IBD and remission, psychological well-being, and QoL. Further studies should investigate how intestinal inflammation, the microbiome, and microbial metabolites affect psychological well-being and whether these components are mono- or bi-directionally linked.