The Brain-Gut Axis: Psychological Functioning and Inflammatory Bowel Diseases

The brain-gut axis represents a complex bi-directional system comprising multiple interconnections between the neuroendocrine pathways, the autonomous nervous system and the gastrointestinal tract. Inflammatory bowel disease (IBD), comprising Crohn's disease and ulcerative colitis, is a chronic, relapsing-remitting inflammatory disorder of the gastrointestinal tract with a multifactorial etiology. Depression and anxiety are prevalent among patients with chronic disorders characterized by a strong immune component, such as diabetes mellitus, cancer, multiple sclerosis, rheumatoid arthritis and IBD. Although psychological problems are an important aspect of morbidity and of impaired quality of life in patients with IBD, depression and anxiety continue to be under-diagnosed. There is lack of evidence regarding the exact mechanisms by which depression, anxiety and cognitive dysfunction may occur in these patients, and whether psychological disorders are the result of disease activity or determinants of the IBD occurrence. In this comprehensive review, we summarize the role of the brain-gut axis in the psychological functioning of patients with IBD, and discuss current preclinical and clinical data on the topic and therapeutic strategies potentially useful for the clinical management of these patients. Personalized pathways of psychological supports are needed to improve the quality of life in patients with IBD.