The gut microbiota is associated with psychiatric symptom severity and treatment outcome among individuals with serious mental illness

• Published in: Journal of affective disorders 2020-03, Vol.264, p.98-106
• Main Authors: Madan, A., Thompson, D., Fowler, J.C., Ajami, N.J., Salas, R., Frueh, B.C., Bradshaw, M.R., Weinstein, B.L., Oldham, J.M., Petrosino, J.F.
• Format: Article
• Language: English
• Subjects: Adult; Animals; Anxiety; Anxiety Disorders; Depression; Gastrointestinal Microbiome - genetics; Humans; Microbiome; Microbiota; Outcomes; RNA, Ribosomal, 16S - genetics; Serious mental illness; Treatment Outcome
• ISSN: 0165-0327; 1573-2517
• DOI: 10.1016/j.jad.2019.12.020

•Depression and anxiety among psychiatric inpatients were negatively associated with richness, alpha diversity, and specific bacterial taxa.•Microbiota richness, alpha diversity, and bacterial taxa early in the hospitalization were associated with depression remission at discharge.•Coprococcus catus may be a significant contributor to the association between the gut microbiota and psychiatric functioning.•A large psychiatric sample from a controlled environment and accounting for confounding variables are clear strengths of the current study. Emerging evidence implicates the gut microbiota in central nervous system functioning via its effects on inflammation, the hypothalamic-pituitary axis, and/or neurotransmission. Our understanding of the cellular underpinnings of the brain-gut relationship is based almost exclusively on animal models with some small-scale human studies. This study examined the relationship between the gut microbiota and psychiatric symptom severity and treatment response among inpatients with serious mental illness. We collected data from adult inpatients (N = 111). Measures of diagnoses, suicide severity, trauma, depression, and anxiety were collected shortly after admission, while self-collected fecal swabs were collected early in the course of hospitalization and processed using 16S rRNA gene sequencing and whole genome shotgun sequencing methods. Results indicate that depression and anxiety severity shortly after admission were negatively associated with bacterial richness and alpha diversity. Additional analyses revealed a number of bacterial taxa associated with depression and anxiety severity. Gut microbiota richness and alpha diversity early in the course of hospitalization was a significant predictor of depression remission at discharge. This study is among the first to demonstrate a gut microbiota relationship with symptom severity among psychiatric inpatients as well as a relationship to remission of depression post-treatment. These findings are consistent with animal models and limited human studies as well as with the broader literature implicating inflammation in the pathophysiology of depression. These findings offer the foundation for further studies of novel therapeutic approaches to the treatment, prevention of, or recurrence of serious mental illness.