Depression and Structural Factors Are Associated With Symptoms in Patients of Irritable Bowel Syndrome With Diarrhea

Background/Aims A strong correlation between depression and irritable bowel syndrome with diarrhea (IBS-D) has been identified. The aim of this study is to identify the correlations among depression, structural factors, gastrointestinal (GI) and extra-GI symptoms, and efficacy of neuromodulators in patients with IBS-D. Methods Patients meeting the Rome III Diagnostic Criteria for IBS-D were enrolled. The intestinal symptoms and psychological states were evaluated using IBS-specific symptom questionnaires and Hamilton Depression Rating Scale. Results In total, 410 patients with IBS-D were enrolled, 28.8% (118/410) had comorbid depression. Patients with depression did not readily experience improvement in abdominal pain/discomfort after defecation, and had a higher prevalence of passing mucus, overlapping functional dyspepsia, and extra-GI symptoms. The structural factor "mental disorders" significantly correlated with main bowel symptom score and degree of pre-defecation abdominal pain/discomfort. No structural factor significantly correlated with bowel movements or stool form. Patients who had passing mucus, overlapping functional dyspepsia and extra-GI painful symptoms have higher score of "anxiety/somatization." Patients with sexual dysfunction have higher score of "retardation symptoms." In total, 28.3% of patients with IBS-D were prescribed neuromodulators. Baseline scores of anxiety/somatization" and "retardation symptoms" positively correlated with improvement of diarrhea after paroxetine, and "sleep disturbances" positively correlated with improvement of abdominal pain/discomfort and diarrhea after mirtazapine. Conclusions Comorbid depression and higher scores of structural factors might aggravate GI and extra-GI symptoms other than bowel movements and stool form. Structural factors of Hamilton Depression Rating Scale correlated with efficacy of paroxetine and mirtazapine in patients with IBS-D.