Background and aims: Somatization disorder, a female predominant disorder, has been found with higher than expected prevalence in previous studies of irritable bowel syndrome (IBS) and might be responsible for some of the comorbidity and excessive health care resource use associated with IBS. The study's aim was to determine within a female IBS population the degree of segregation of psychiatric illness, functional disorders, and health care utilization with somatization disorder.
Methods: In a prospective, 6-month follow-up study, psychiatric disorders were assessed with the Diagnostic Interview Schedule, gastrointestinal and other symptoms with self-report questionnaires, and medically unexplained complaints by thorough chart review. The setting was a university gastroenterology clinic. The participants were a convenience sample of female clinic attendees with IBS (N = 56).
Results: Somatization disorder was diagnosed in 25% of patients and highly probable in another 5%. Somatization disorder was associated with significantly greater numbers of gastrointestinal and other symptoms, psychiatric disorders, physicians consulted, telephone calls to physicians, urgent care visits, medication changes, and missed work days and with benzodiazepine use. On follow-up, somatization disorder was associated with psychiatric and IBS symptoms, medication changes, and treatment dissatisfaction. Both somatization disorder and other psychiatric illnesses were associated with other functional gastrointestinal disorders; only somatization disorder remained predictive in a regression model that controlled for the presence of other psychiatric illness.
Conclusions: Among female IBS patients attending a university gastroenterology clinic, many aspects of comorbidity and health care behaviors previously associated with IBS segregated with the diagnosis of somatization disorder. Recognition and appreciation of somatization disorder in IBS have important ramifications for the conduct of research and clinical practice.