Research Explores Connection Between Bacteria and Depression, Anxiety


The results suggest that the bacterium Lactobacillus may aid in the management of stress and in the prevention of these disorders.



Research from the University of Virginia (UVA) School of Medicine identified a potential connection between the gut bacterium, Lactobacillus, and the management of stress, potentially impacting depression and anxiety.

The study—led by Alban Gaultier, PhD, of the UVA Department of Neuroscience, the Center for Brain Immunology and Glia (BIG Center), and the TransUniversity Microbiome Initiative—aimed to understand how this specific bacterium influences mood disorders by interacting with the immune system.1

“We were aware from our prior research that Lactobacillus was beneficial in improving mood disorders and was lost following psychological stress,” Gaultier said in a news release, “but the underlying reasons remained unclear, primarily due to the technical challenges associated with studying the microbiome.”

Recognizing the importance of microbiota in immune and mental health, Gaultier and colleagues explored the use of probiotics to manipulate gut flora, with varying outcomes. Utilizing the Altered Schaedler Flora collection, they conducted experiments on mice both with and without Lactobacillus, revealing specific behavioral impacts and associations with depression and anxiety.1,2

The investigators found that the protective effects against environmental stressors were attributed to the Lactobacillus species rather than to the disturbed microbial communities. Their findings indicated that Lactobacillus plays a crucial role in sustaining homeostatic interferon gamma (IFNγ) levels, which, in turn, mediate the observed behavioral and circuit-level responses.2

UVA officials noted that Lactobacillus, part of a significant bacteria family, appears to regulate the immune mediator interferon gamma, which is linked to the body’s stress response and potential depression prevention.1

The implications of these results for depression suggest a potential connection between gut microbiota, particularly the Lactobacillus species, and the manifestation of depressive symptoms. “Our discovery illuminates how gut-resident Lactobacillus influences mood disorders by tuning the immune system,” Gaultier said in a news release. “Our research could pave the way towards discovering much-needed therapeutics for anxiety and depression.”

Moving forward, the investigators plan to further investigate the role of Lactobacillus in mental health conditions and other potential avenues for prevention and treatment.1

“With these results in hand, we have new tools to optimize the development of probiotics, which should speed up discoveries for novel therapies,” said Andrea R. Merchak, PhD, one of the study investigators, in a news release. “Most importantly, we can now explore how maintaining a healthy level of Lactobacillus and/or interferon gamma could be investigated to prevent and treat anxiety and depression.”

The results of this study were recently published in the journal, Brain, Behavior, and Immunity. Read the full study here.

Stay up-to-date on news related to research on promising new interventions and developments in the treatment of a wide variety of other psychiatric disorders at

Note: This article was prepared with the assistance of ChatGPT.


1. UVA scientists uncover how bacteria could guard against depression, anxiety. WTVR CBS 6. News release. November 28, 2023. Accessed November 30, 2023.

2. Merchak AR, Wachamo S, Brown LC, et al. Lactobacillus from the Altered Schaedler Flora maintain IFNγ homeostasis to promote behavioral stress resilience. Brain Behav Immun. 2024;115:458-469.

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