[Irritable bowel syndrome--a multifactorial disease in children and adults].

Irritable bowel syndrome is the most frequent gastrointestinal disorder in Norway. Though there has been huge research activity in the field, no proven single aetiology or effective treatment has emerged. Consensus-based clinical diagnostic criteria have not yet brought diagnostic clarity. Possibly, there are dysfunctions in the processing of sensory stimuli in the "brain-gut" axis that may cause visceral hypersensitivity and secondary motility changes. In some patients, a multifactorial explanation of the mechanisms is useful, including stressful life events or other psychological factors. Psychiatric co-morbidity is probably the most important maintaining factor. Irritable bowel syndrome may serve as a model for the study of the interaction between biological, psychological and social factors in functional disorders. A good therapeutic relationship between the physician and the patient is an important element in the treatment approach.