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Study looks at ties between anxiety and gut bacteria

UT Southwestern-led team investigates relationship between microbiome, symptoms among patients with depression

Conceptual illustration of the gut microbiome. The gut microbiome refers to all of the microbes in the intestines. These microbes influence many aspects of health, including the immune system, and they help digest food
UT Southwestern researchers are studying microorganisms within the gut microbiome, shown in this conceptual illustration, that may be associated with anxiety levels. (Photo credit: Getty Images)

DALLAS – Nov. 8, 2023 – Interactions among microorganisms within the human gut may be associated with increased anxiety levels in people with depression, according to research led by UT Southwestern Medical Center.

Using advanced bioinformatics tools like 16S rRNA gene sequencing, researchers analyzed stool samples from 178 patients with a current or past diagnosis of depression who are part of an ongoing Texas Resilience Against Depression (T-RAD) study. The analysis, published in Translational Psychiatry, revealed three networks of gut microbial communities, one of which was correlated with anxiety. While the early findings raise the possibility that gut bacteria could affect anxiety levels, further validation is needed to confirm whether there is a relationship and how that might translate to a clinical setting.

Jane Foster, Ph.D
Jane Foster, Ph.D., is Professor of Psychiatry and in the Center for Depression Research and Clinical Care and an Investigator in the Peter O’Donnell Jr. Brain Institute at UT Southwestern.

“This novel approach allowed us to consider the community of bacteria in the gut rather than individual bacteria. One specific microbial community was enriched with butyrate-producing bacteria, and we found that individuals with a low abundance of these key bacteria had higher anxiety,” said Jane Foster, Ph.D., Professor of Psychiatry and in the Center for Depression Research and Clinical Care (CDRC) at UT Southwestern.

A UTSW-led team developed the two longitudinal studies that make up T-RAD, D2K and RAD, in 2020. Spanning 10-plus years and each enrolling 2,500 participants, including from Children’s Health and Parkland Health, the studies aim to comprehensively understand depression onset, recurrence, progression, and treatment response. The work is similar to the hallmark Framingham Heart Study that identified risk factors that now serve as gold-standard metrics for heart disease.

Gut microbiota was one of the first biological markers examined by T-RAD because of its role as a key modulator of human physiology and its strong relationship with mood regulation. Dr. Foster was part of the first research group to connect microbiota to anxiety-like behavior in mice about 15 years ago.

Madhukar Trivedi, M.D.
Madhukar Trivedi, M.D., is Professor of Psychiatry, Chief of the Mood Disorders Division, and founding Director of the Center for Depression Research and Clinical Care. Dr. Trivedi is also an Investigator in the Peter O'Donnell Jr. Brain Institute at UTSW.

“Understanding the role of specific microbacteria for the anxiety subtype of depression is exciting. This will extend our research into precise treatment targets using further studies with the gut microbiome to complement our previous findings with brain-based biomarkers,” said Madhukar Trivedi, M.D., Professor of Psychiatry, Chief of the Mood Disorders Division, and founding Director of the CDRC. Drs. Trivedi and Foster are also Investigators in the Peter O’Donnell Jr. Brain Institute at UTSW.

Although most studies have focused on single types of bacteria and their association with illness, the current study seeks clinically relevant affiliations when looking at broader bacterial community structures. This suggests that the study’s approach may provide a more accurate view of bacterial communities that are linked with specific symptoms in patients.

“In this study, we looked at individuals with a current or previous diagnosis of major depressive disorders. But the importance of the microbiome-brain connections extends to healthy individuals as well as the broader fields of psychiatry and neurology,” Dr. Foster said. “The next step will be to validate biomarkers that define individual differences, which could help develop precision approaches to treating depression.”

Other UTSW researchers who contributed to this study are Cherise Chin Fatt, Ph.D., Assistant Professor of Psychiatry; Manish Jha, M.D., Associate Professor of Psychiatry and an O’Donnell Clinical Neuroscience Scholar; Abu Taher Minhajuddin, Ph.D., Professor of Psychiatry in the Peter O’Donnell Jr. School of Public Health; Sangita Sethuram, M.B.A., Performance Improvement Manager at the CDRC; and Taryn L. Mayes, M.S., Program Manager at the CDRC.

Dr. Trivedi holds the Betty Jo Hay Distinguished Chair in Mental Health and the Julie K. Hersh Chair for Depression Research and Clinical Care.

This study was funded by The Hersh Foundation, the Rose Foundation, the Ontario Brain Institute, and the CDRC at UT Southwestern.

About UT Southwestern Medical Center  

UT Southwestern, one of the nation’s premier academic medical centers, integrates pioneering biomedical research with exceptional clinical care and education. The institution’s faculty members have received six Nobel Prizes and include 26 members of the National Academy of Sciences, 20 members of the National Academy of Medicine, and 13 Howard Hughes Medical Institute Investigators. The full-time faculty of more than 3,100 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in more than 80 specialties to more than 120,000 hospitalized patients, more than 360,000 emergency room cases, and oversee nearly 5 million outpatient visits a year.