Panic disorder(PD) and irritable bowel syndrome(IBS) have many common symptoms, which are psychological symptoms and dysautonomic symptoms. We hypothesized that there are common underlying mechanisms in PD and IBS. To test our hypothesis, we examined the prevalence and precise symptomatic analysis of IBS in patients with PD. Subjects were 85 PD patients diagnosed by DSM-IV and 75 healthy controls whose age and sex were almost matched. We developed panic symptoms questionnaire based on DSM-IV and IBS symptoms questionnaire based on Rome criteria. Both questionnaires were self-reported by the subjects and their symptoms were graded and quantified. Twenty PD patients (24%) and 8 controls (11%) satisfied diagnostic criteria for IBS. The prevalence of HBS was significantly higher in PD patients than controls (p<0.05, x^2 test). In PD patients with IBS (n=20), IBS preceded PD in 14 patients (70%), PD preceded IBS in 5 patients (25%) and two conditions occurred concurrently in 1 patients (5%). Psychosocial stress aggravated abdominal symptoms in 34 PD patients (40%) and 18 controls (24%), indicating significantly higher rate of exacerbation in PD patients than controls (p<0.05, x^2 test). During panic attacks, PD patients complained of nausea in 34 (40%), abdominal pain in 29 (34%) and abdominal discomfort in 34 (40%). The PD patients with IBS had significantly severe panic symptoms, nausea/abdominal distress, choking, chest pain/chest discomfort, dizziness, derealization, fear of losing control, and paresthesia, than the PD patients without IBS (p<0.05, Mann-Whitney U-test). Comorbidity of IBS in patients with PD likely aggravates panic symptoms. These data suggest that PD may have, at least in part, common pathogenesis with IBS.
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