Emotional stress responsivity of patients with IBS - a systematic review.

Objective: Irritable bowel syndrome (IBS) is a highly prevalent disorder of the gut-brain interaction characterized by abdominal discomfort and pain associated with altered bowel habits in the absence of structural abnormalities. Chronic psychological stress is considered a risk factor for the development of IBS. The multifactorial pathogenesis involves complex interactions between biological, psychological and social factors, yet the underlying mechanisms have not been fully understood.

Methods: We systematically reviewed the literature from the databases MEDLINE, Embase and PsycINFO to assess stress responsivity of patients with IBS in comparison to healthy individuals, specifically focusing acute psychological stressors.

Results: A total of 37 case-control studies were included in the narrative synthesis. Findings comprised subjective changes in emotion (k = 18) and of gastrointestinal symptoms (k = 8) as well as objective parameters of gastrointestinal motility (k = 10), autonomic nervous system (k = 23), hypothalamic-pituitary-adrenal axis (k = 11), functional brain activity (k = 7) and immune system (k = 3). Mental stress was found to increase IBS-specific symptomatology and alter gastrointestinal motility. Some patients with IBS showed stress-induced emotional hyperresponsivity and different patterns of neural activation. Autonomic and endocrine stress responses depend on the type of stressor and showed no clear evidence of differential reactivity, partly due to confounding factors. Data on acute immunological changes remains sparse and requires further investigation.

Conclusions: Current evidence suggests altered stress reactivity in patients with IBS however, it remains unclear whether it can be attributed to the syndrome itself or the high prevalence of psychiatric comorbidities.