Gut-Brain Axis Review Explores Microbiome's Bidirectional Role in PTSD Pathophysiology and Therapy

Post-traumatic stress disorder (PTSD) presents significant inter-individual variability in vulnerability and is linked to chronic disease comorbidities, with underlying mechanisms remaining unclear. Current understanding points to chronic psychological stress and stress hormones like cortisol modulating microbial composition and immune function. The gut microbiome is emerging as a crucial mediator, potentially linking stress exposure to immune and neurobiological changes. This bidirectional communication between the gut and brain offers a novel lens to understand PTSD development and its diverse manifestations.

This narrative review systematically synthesized existing literature to explore the intricate relationship between the gut-brain axis and post-traumatic stress disorder (PTSD). Researchers focused on identifying the biological mechanisms underpinning this connection and evaluating potential microbiome-based therapeutic strategies. The review examined how stress-induced hormonal signaling and host factors influence microbial composition, and conversely, how microbiome alterations modify stress responsiveness, providing a comprehensive overview of the bidirectional communication network.

The review highlights compelling evidence for a bidirectional communication network between the gut microbiota and the central nervous system, termed the brain–gut–microbiota axis. It establishes that PTSD is associated with significant gut microbiota dysbiosis, an imbalance within the microbial ecosystem, which can profoundly impact immune regulation, metabolic function, and neurodevelopment. Stress-induced hormonal changes, such as elevated cortisol, are shown to directly modulate microbial composition, while altered microbial profiles can in turn modify host stress responsiveness.

The synthesis reveals that gut microbiota dysbiosis is not merely a consequence of PTSD but actively contributes to its pathophysiology, influencing neurobiological alterations and systemic inflammation.

Furthermore, the review identifies several potential therapeutic avenues targeting the microbiome, including probiotics, prebiotics, and fecal microbiota transplantation, suggesting these interventions could modulate the gut-brain axis to alleviate PTSD symptoms and associated comorbidities. The intricate interplay of microbial metabolites, immune pathways like NF-κB, and neurotransmitter systems is emphasized as central to this axis.