A total of 193 IBS patients, diagnosed according to Rome II (n = 126) or Rome III (n = 67) criteria, consumed a standard breakfast (540 kcal: 36% fat, 15% proteins, 49% carbohydrates, and 8.9 g fiber). They completed visual analogue scales assessing the severity of 5 gastrointestinal symptoms (abdominal pain, bloating, nausea, gas, and fullness) before breakfast and every 30 minutes, up to 240 minutes after eating. All patients completed validated self-report questionnaires for their current levels of anxiety and depression; patients diagnosed based on Rome II criteria also completed a somatization questionnaire. The relationship between these variables and the course of gastrointestinal symptom scores over time was analyzed using linear mixed models, controlling for comorbid functional dyspepsia.
We observed a main effect of anxiety levels on fullness and bloating (P < .04), and of depression levels on abdominal pain (P = .007), reflecting a general upward shift of the entire symptom curve. Depression-by-time interactions were seen for nausea and gas (P < .03). Somatization levels had a main effect on all 5 symptoms (P < .0001), independent of anxiety and depression. We observed somatization-by-time interaction effects for bloating (P = .005), and nausea (P = .02), and a nonsignificant trend was found for pain (P = .054), reflecting a steeper early postprandial increase in symptoms among subjects with higher levels of somatization.
Based on a prospective study of patients with IBS, psychosocial morbidities are associated with increased levels of gastrointestinal symptoms in general. Depression and somatization levels are associated specifically with increased postprandial symptoms.