Psychological Factors in Irritable Bowel Syndrome: a Population-based Study of Patients, Non-patients and Controls.

Background: It has been suggested that psychopathology in irritable bowel syndrome (IBS) patients is a function of patient status rather than of the disease. Although there are many studies comparing IBS patients, IBS non-patients, and controls with each other, no previous study has recruited all three groups from a representative community sample and had all subjects diagnosed by a physician. In the present study we aimed to compare psychological factors in IBS patients, IBS non-patients, and normal controls in a sample recruited from the population.

Methods: Subjects aged 18-45 years were recruited from a random sample of the normal population. Seventeen (2 M and 15 F) IBS patients were matched by sex and age with IBS non-patients and normals. Measures of personality traits, interpersonal distress, and temporary psychological distress were used. A physician diagnosed all 51 subjects in order to exclude possible gastrointestinal diagnoses other than IBS.

Results: Controls often differed from IBS non-patients and patients on the personality, interpersonal, and psychological distress measures, while IBS non-patients and patients very rarely differed from each other. All three groups were non-alexithymic.

Conclusions: The results indicate that there are psychopathological differences between normals and IBS persons (patients and non-patients), but they could not confirm that psychopathology was a function of patient status. Whether this psychopathology is a vulnerability factor for IBS, or a consequence of it, remains to be studied.