Stress, microbiota, and the gut-brain axis in mental and digestive health

The prevailing mind-body dualism in contemporary medicine, rooted in reductionism and the fragmentation of knowledge, has impeded the development of a conceptual model that can adequately address the complexity of illnesses. Integrating biomedical data into a cohesive model that considers the mind-body-context interconnections is essential. This integration is not merely theoretical; rather, it has significant clinical implications. This is exemplified by chronic stress-related mental and digestive disorders. The onset and development of these disorders are intimately linked to chronic psychological stress via the brain-gut-microbiota axis. The present article examines the evidence and mechanisms indicating that stress is a primary factor and a potentiator of symptom severity in common mental health and digestive diseases, with a particular focus on human studies. However, due to space limitations, only a very general overview of preventive and therapeutic clinical strategies is provided. It is hoped that the recurring phrase, "Everything that happens to you is due to stress," will become more comprehensible to the physician after reading this manuscript.