Microbiome and PTSD

Information

Posttraumatic Stress Disorder (PTSD) is a complex psychiatric condition that develops in some individuals following exposure to traumatic events. While not everyone exposed to trauma develops PTSD, susceptibility appears to be influenced by multiple biological and environmental factors — including, increasingly, the human gut microbiome.

The gut microbiome refers to the trillions of microorganisms, including bacteria, viruses, fungi and archaea, that inhabit the digestive tract. Emerging evidence suggests that the composition and diversity of these microbial communities may play a role in mental health. Recent studies point to associations between altered gut microbiota — or dysbiosis — and mood or anxiety disorders. Interventions targeting the microbiome, such as probiotics or dietary changes, are showing promise in clinical trials.

In PTSD specifically, research has identified shifts in the gut microbiome, including changes in the relative abundance of certain bacterial taxa. However, findings across studies vary considerably, likely due to differences in study design, populations, and unaccounted confounding variables such as diet, medication use, and socio-demographic factors. Of particular interest is the role of ethnicity, which has been shown to influence both microbiome composition and PTSD prevalence, yet remains understudied in this context.

To better understand these relationships, our project combines two complementary approaches:

A Scoping Review of current scientific literature on the microbiome–PTSD connection, with a focus on taxonomic and functional changes, potential mechanisms, and gaps in research.

Empirical Analysis of data from the HELIUS (Healthy Life in an Urban Setting) study, a large multi-ethnic cohort in the Netherlands. This analysis will explore the associations between gut microbiome features and PTSD symptom levels, while controlling for potential confounders including age, sex, socioeconomic status, diet, medical history, and lifestyle factors.

Our primary research aim is to identify microbiome characteristics — both taxonomic and functional — that are linked to PTSD symptom severity. The secondary aim is to investigate how these associations may vary across ethnic groups, thereby contributing to a more nuanced and inclusive understanding of the gut-brain axis in trauma-related disorders.

By combining systematic review with robust cohort data, this project aims to clarify the role of the gut microbiome in PTSD and assess the potential for microbiota-based interventions that are applicable across diverse populations.

Research Team

Dr. Ronja Berendse – PhD Candidate

Hannah van Houten – MSc Student

Dr. Jasper Zantvoord – Psychiatrist

Dr. Marieke Verkleij – Postdoctoral Researcher & Psychologist

Dr. Aniko Korosi – Neuroscientist

Dr. Thomaz Bastiaansen – Postdoctoral Researcher & Bioinformatician

Prof. Sian Hemmings – Professor of Molecular Biology and Psychiatry, Stellenbosch University, South Africa

Dr. Anja Lok – Principal Investigator