- Background High rates of psychiatric co-morbidity have been reported in patients with irritable bowel syndrome (IBS) and high rates of post-traumatic stress disorder (PTSD) have been reported in fibromyalgia, a disorder also associated with IBS. The primary aim of this study was to assess the frequency of PTSD in IBS patients. Methods Sixty-four patients who fulfilled the Rome II diagnostic criteria for IBS were asked to complete questionnaires measuring the prevalence and severity of symptoms of PTSD and psychological distress. Results Although 86% of IBS patients reported a traumatic life experience, only 7.8% met the diagnostic criteria for PTSD. High rates of somatization, obsessive-compulsive behavior, interpersonal sensitivity, and anxiety symptoms were seen among the IBS patients. Conclusions The results show a lower than expected prevalence of PTSD among IBS patients, which is similar to that of the general population. Thus, we did not find that PTSD is over-represented in a sample population of IBS patients.