Previous research has shown that psychological treatments, particularly those employing cognitive techniques, are particularly effective in the treatment of irritable bowel syndrome (IBS). It is presumed that these psychological interventions are effective at ameliorating the IBS by treating an underlying psychological disorder (often an anxiety disorder), which may be contributing to the autonomic reactivity. This case study examined the change in the physical symptoms of IBS for a patient seeking treatment for rape-related PTSD with comorbid conditions of major depression and panic. At posttreatment, the patient no longer met criteria for PTSD, major depression, or panic. In addition, her primary symptom of IBS, diarrhea frequency, was significantly improved. These findings were maintained at 3 and 9 months posttreatment. Implications for the assessment and treatment of IBS patients with PTSD are discussed.The complex interplay between the psychological and physical impact of stressful life experiences has been receiving increased attention (Cohen & Williamson, 1991;Herbert & Cohen, 1993;Watson & Pennebaker, 1989). A condition particularly illustrative of this interplay is irritable bowel syndrome (IBS). IBS is a functional disorder of the lower gastrointestinal (GI) tract primarily characterized by cramping abdominal pain and bowel disruptions, which may include diarrhea or constipation, separately or alternating periods of each condition (Drossman, 1994). While the issue of a truly causal relationship between ongoing (daily) stressors and IBS symptoms has been questioned (Suls, Wan, & Blanchard, 1994), correlational research suggests that psychosocial stressors play an important role in IBS symptom initiation (Craig & Brown, 1984; Mendeloff, Monk, Siegel, & Lilienfeld, 1970) and exacerbation (Drossman et al., 1988).Recently, researchers have found that stressful experiences of a traumatic nature have distinguished treatment-seeking patients with functional GI illness (IBS) from patients with organic GI illness, such as inflammatory bowel disease (Drossman et al., 1990;Walker, Gelfand, Gelfand, & Katon, 1995). Treatment-seeking IBS patients are also more likely to report higher rates of psychiatric diagnoses compared with patients with inflammatory bowel disease (Blanchard, 1993;Greene & Blanchard, 1994;Walker et al., 1995). Many of these diagnoses have been in the spectrum of anxiety disorders, with particularly high rates of generalized anxiety disorder (GAD) reported (Blanchard). Anxiety disorders can include symptoms of fixed perceptions of threat, anticipation of problems, and catastrophizing. These characteristic symptoms may then trigger physiological (GI) hyperarousal associated Copyright 1998 by Association for Advancement of Behavior Therapy, All rights of reproduction in any form reserved.Correspondence concerning this article should be addressed to Terri L. Weaver, Center for Trauma Recovery and Department of Psychology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Lo...