Can probiotics help treat depression?

In a pilot clinical trial published in the Journal of the American Geriatrics Society that included older adults with depression receiving standard care, adding probiotic therapy produced modest but meaningful reductions in depressive and anxiety symptoms compared with adding a placebo. However, both groups demonstrated substantial overall improvements during follow-up.

For the trial, 58 participants in India aged ≥60 years with moderate depression were randomized 1:1 to receive daily probiotics or a placebo for 12 weeks, alongside standard antidepressant care. They were followed up for another 12 weeks.

Based on validated psychological scores, biomarker (serum brain-derived neurotropic factor level), and fecal microbiota profiling, investigators found that probiotics helped improve patients’ symptoms but did not confer clear additional gains in quality of life compared with placebo. The findings support probiotics as a safe, biologically plausible adjunct to standard care, but larger trials are needed.

"The results of our study are novel, and we are now planning a follow-up, larger-scale clinical trial due to the encouraging findings," said co-corresponding author Dr. Saibal Das, MBBS, MD, DM, PhD, of the Indian Council of Medical Research - National Institute for Research in Bacterial Infections, Kolkata. “My vision is to develop affordable healthcare solutions and make them available to the larger population for meaningful public health impact,” added co–corresponding author Abhinaba Ghosh, MBBS, MSc, PhD, a physician-neuroscientist from Tata Medical Center, Kolkata.

Reference:

P. Sinha, P. Chatterjee, P. Kathiresan, et al., “Efficacy of Adjunct PRObiotics as Compared to the Standard Care in Moderate Unipolar Depression Among Geriatric Patients: A Randomized Double-Blind Placebo-Controlled Pilot Multi-Center Trial (PRODG),” Journal of the American Geriatrics Society (2026): 1–11, https://doi.org/10.1111/jgs.70530.