Fecal microbiota transplant may help patients with IBS and depressive symptoms

A meta-analysis of randomized trials suggests fecal microbiota transplantation can ease depressive symptoms, with stronger effects reported for endoscopic or enema delivery, according to researchers at the Department of Nursing, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine. A subset also found improvements in irritable bowel syndrome (IBS).

Global estimates from 2021 place depression at more than 280 million cases. Many patients do not achieve adequate relief with medication or psychotherapy. Growing work on the microbiota–gut–brain axis describes altered gut composition in depression and links between microbial metabolites and mood regulation.

Disorders of gut–brain interaction such as IBS show high psychiatric comorbidity, positioning microbiota-targeted strategies as candidates for symptom relief.

In the study, “Clinical efficacy of fecal microbiota transplantation in alleviating depressive symptoms: a meta-analysis of randomized trials,” published in Frontiers in Psychiatry, researchers synthesized randomized controlled trials to determine whether restoring gut microbial balance could improve mood outcomes.

Twelve randomized trials conducted between 2019 and 2024 across China, Australia, Canada, Finland, and the United States contributed data on 347 treatment participants and 334 controls. Investigators compared fecal microbiota transplantation with placebo, autologous transplant, or standard medication.

Procedures included oral capsule, colonoscopic, gastroscopic, jejunal, rectal, or transendoscopic delivery, depending on study design. Follow-up durations ranged from two weeks to 12 months.

Results indicate a pooled reduction in depressive symptoms favoring fecal microbiota transplantation over control groups. Oral capsules and direct gastrointestinal administration both met significance, with a larger pooled effect for direct routes such as colonoscopy or enema compared with oral delivery.

Analysis showed both short-term and intermediate-term benefits, with long-term effects at or beyond six months not reaching statistical significance of an improvement.

Clinical subgrouping suggested a larger effect in IBS cohorts than in neurological or psychiatric conditions including major depressive disorder, Parkinson’s disease, and progressive supranuclear palsy–Richardson’s syndrome. Publication bias appeared minimal across studies.

The authors conclude that fecal microbiota transplantation may function as an adjunctive option for depressive symptoms, with signals favoring IBS populations and endoscopic or enema delivery over capsules. Durability beyond six months remains uncertain and calls for longer, higher-quality randomized trials and additional dosing.

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