The neurobiology of stress and gastrointestinal disease

The role of stress in the modulation of the most common gastrointestinal disorders has traditionally been considered a domain of psychology, and has frequently been lumped together with the role of psychiatric comorbidity. Among clinicians, the term “stress” is generally taken as synonymous with psychological (“exteroceptive”) stress. Based on the deeply ingrained Cartesian view in medicine and gastroenterology, stress and psychological factors have been considered fundamentally separate and unrelated to the “real” biological changes underlying organic disease. However, recent breakthroughs in the understanding of the neurobiology of the organism's response to acute and chronic stress, and the evolving understanding of elaborate brain-gut interactions and their modulation in health and disease, are beginning to require a reassessment of chronic stress in the pathophysiology and management not only of functional but also of “organic” gastrointestinal disorders. Certain stressful life events have been associated with the onset or symptom exacerbation in some of the most common chronic disorders of the digestive system, including functional gastrointestinal disorders (FGD), inflammatory bowel disease (IBD), gastro-oesophageal reflux disease (GORD), and peptic ulcer disease (PUD). Even though methodological differences in reported studies which do and do not support such an association remain to be resolved, the association of sustained stressful life events preceding symptom exacerbation is based on several well designed surveys in patients with FGD,1-4with post-infectious irritable bowel syndrome (IBS),4 and with IBD.5-8 In addition, acute life threatening stress episodes in adult life (rape, post-traumatic stress syndrome) are an important risk factor in the development of functional gastrointestinal disorders.9 Finally, early life stress in the form of abuse plays a major role in the susceptibility of individuals to develop functional as well as IBD10-14 later in life. Thus, depending on the type of stressor, the lag time between the stressful event …