Brain, behavior, & immunity - healthSep 2, 2025

Changes in gut bacteria types and functions in people with major depression and recent suicide attempts

Gut-Brain Axis Weekly Brief ↗PubMed ↗DOI ↗

Updated Jun 27, 2026

Abstract

Essence

Recent suicide attempts in hospitalized MDD patients were associated with altered gut microbial diversity and predicted metabolic potential.

Evidence

This exploratory observational microbiome study compared fecal 16S rRNA and shotgun sequencing from 35 MDD patients with recent suicide attempts and 15 without suicide history.

Caveat

The small hospitalized cohort and observational design cannot determine whether microbiome differences contribute to suicide risk or reflect illness, treatment, or hospitalization factors.

Simplified

This study investigates the role of the gut microbiome in suicidal behavior among individuals with major depressive disorder (MDD). Fecal samples from 50 hospitalized patients with MDD, including 35 with recent suicide attempts (60 % female) and 15 without a history of suicide (73 % female), were analyzed using 16S rRNA and shotgun sequencing to assess microbiome diversity and metabolic potential. Results revealed that suicide attempters exhibited significantly greater microbial richness and distinct beta-diversity patterns. Notably, they had higher levels ofand lower levels of. Additionally, 25 metabolic pathways differed between groups, with several linked to energy metabolism and amino acid processing-processes previously associated with MDD and suicidal behavior. These findings suggest that microbiome composition may influence suicide risk through gut-brain axis-mediated pathways, although due to the exploratory nature of this study further investigation is needed to validate our findings. Given the microbiome's modifiability, future research should explore microbial-targeted interventions as a potential strategy for suicide prevention in individuals with MDD. Fenollaria timonensis Corynebacterium aurimucosum