A study of the association between Crohn's disease and psychiatric illness.

This study is an examination of the association between Crohn's disease and psychiatric illness using careful gastrointestinal evaluation, a structured psychiatric interview of known reliability and validity, and explicit diagnostic criteria for psychiatric illness. A proband sample of 50 subjects with Crohn's disease was obtained from a university clinic and a private clinic. Fifty control subjects with chronic medical illnesses obtained from the same two clinic sources were also examined. Compared with controls, a significantly greater number of the patients with Crohn's disease met criteria for some psychiatric disorder at some time in their lives, and a significantly greater number had a diagnosis of depression. A greater number of the probands reported obsessional or phobic symptoms, and the mean number of obsessional symptoms was higher in probands than in controls. We found no evidence of an interaction between psychiatric disorder and Crohn's disease. The significance of the discovered association for the treatment and natural history of Crohn's disease is discussed.