Summary: Adding probiotic therapy to standard care can provide modest but meaningful relief for older adults suffering from moderate depression. The study monitored 58 participants aged 60 and older over 24 weeks using fecal microbiota profiling and serum brain-derived neurotrophic factor (BDNF) biomarkers.
While both groups experienced significant baseline recovery due to standard care, the probiotic cohort showed distinct reductions in depressive and anxiety symptoms, positioning probiotics as a safe, affordable, and biologically sound adjunctive treatment for late-life depression.
Key Facts
- Targeted Geriatric Relief: Daily probiotic supplements introduced alongside standard antidepressant care led to modest but meaningful drops in anxiety and depressive symptoms in adults aged 60 and older.
- Biomarker and Microbe Tracking: The 24-week pilot trial utilized rigorous testing metrics, including fecal microbiota profiling and tracking blood levels of brain-derived neurotrophic factor (BDNF).
- High Baseline Improvement: Both the probiotic and placebo cohorts demonstrated substantial clinical improvements over the course of the study, highlighting the efficacy of standard antidepressant care.
- Quality of Life Plateau: While psychological symptom scores improved, the probiotic group did not show clear additional gains in overall self-reported quality of life metrics compared to the placebo group.
- Affordable Public Health Goal: Researchers are currently organizing a larger-scale clinical trial with the ultimate goal of developing scalable, low-cost probiotic interventions for widespread public health use.
Source: Wiley
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.
Key Questions Answered:
A: BDNF is a crucial protein that acts like a growth fertilizer for neurons in the brain, supporting brain plasticity, learning, memory, and cell survival. Chronically low levels of BDNF are strongly linked to brain cell atrophy and the development of clinical depression. Tracking changes in serum BDNF levels allows neuroscientists to physically measure whether a treatment is successfully stimulating the brain’s internal repair and recovery mechanisms.
A: The gut and the brain are in constant communication via the gut-brain axis, a complex biochemical signaling highway managed by the vagus nerve, immune system molecules, and microbial metabolic byproducts. When beneficial live bacteria from a probiotic populate the gastrointestinal tract, they alter local inflammatory pathways and produce neurotransmitter precursors. This shift effectively calms systemic inflammation and sends regulatory signals back up to the brain, helping to stabilize mood and ease anxiety.
A: As a pilot trial, this study featured a relatively small sample size of 58 participants. Additionally, because both the placebo group and the probiotic group showed massive overall improvements from their standard care, a much larger, multi-center sample size is required to fully separate the distinct, independent therapeutic power of the probiotics from the placebo effect and establish definitive guidelines for clinical practice.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this depression research news
Author: Sara Henning-Stout
Source: Wiley
Contact: Sara Henning-Stout – Wiley
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Efficacy of Adjunct PRObiotics in Moderate Unipolar Depression in Geriatric Patients: A Randomized Double-Blind Multicentric Trial (PRODG)” by Preeti Sinha, Prasun Chatterjee, Preethy Kathiresan, Karishma Sundara Raju, Rasika Panwar, Aparna Mukherjee, Gunjan Kumar, Jerin Jose Cherian, Anoop Velayuthan, Avinash Chakrawarty, Sarnendu Mondal, Manoj Kalita, Spriha Kamboj, Sreyashi Sen, Mounamukhar Bhattacharjee, Manaswini Mondal, Kalyan Bhowmik, Sovonlal Mukherjee, Indranil Saha, Atanu Kumar Dutta, Asim Saha, Amit Chakrabarti, Abhinaba Ghosh, Saibal Das. Journal of the American Geriatrics Society
DOI:10.1111/jgs.70530
Abstract
Efficacy of Adjunct PRObiotics in Moderate Unipolar Depression in Geriatric Patients: A Randomized Double-Blind Multicentric Trial (PRODG)
Objective
To evaluate the efficacy of adjunct probiotic supplementation (Lactobacillus helveticus and Bifidobacterium longum) alongside standard care compared to placebo in older adults with moderate unipolar depression.
Methods
A randomized, double-blind, placebo-controlled pilot trial was conducted at two tertiary centers. Fifty-eight participants (≥ 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. The primary outcome was depression response (≥ 50% Montgomery-Åsberg Depression Rating Scale [MADRS] score reduction). Secondary outcomes included anxiety (General Anxiety Disorder 7-Item [GAD-7]), cognition, quality of life (WHOQOL-BREF), serum brain-derived neurotropic factor (BDNF), and gut microbiota profile.
Results
Mixed-effects models showed significant improvement over time in depressive symptoms (MADRS: F = 32.0, p < 0.001) and anxiety (GAD-7: F = 13.1, p < 0.001). Overall scores were lower in the probiotic group compared with the placebo group for both MADRS (F = 12.7, p = 0.001) and GAD-7 (F = 10.7, p = 0.002), although group × time interactions were not significant. Quality-of-life domains improved markedly (all F > 100, p < 0.001) without additional benefit from probiotics. Escitalopram-equivalent antidepressant dose and benzodiazepine use influenced selected outcomes. The probiotic group also had a significantly higher serum BDNF level and increased fecal abundance of supplemented strains vs. the placebo group. The attrition rate was > 50% over 24 weeks.
Conclusion
In this pilot PRODG trial, adjunct probiotics produced modest overall advantages for depressive and anxiety symptoms compared with placebo but did not enhance quality-of-life beyond usual improvement − both groups improved substantially, and trajectories over 24 weeks were largely parallel across follow-up.
