Behavioral and physiological sleep characteristics in women with irritable bowel syndrome

Objectives: The goal of this study was to investigate behavioral (self-reported) and physiological sleep characteristics in irritable bowel syndrome (IBS) patients with and without concurrent dyspeptic symptoms, as compared to control subjects. Methods: A total of 31 women with IBS were stratified into two groups: 15 with bowel symptoms only (IBS-only) and 16 with both lower and upper dyspeptic symptoms (IBS+D). In addition, 23 healthy women served as controls. For 4 consecutive days, subjective sleep quality, insomnia symptoms, alertness, state anxiety, perceived daytime stress, and daytime and nighttime GI symptoms were assessed. On night 4, subjects underwent polysomnographic (PSG) monitoring, for an objective assessment of sleep quality including microarousals and respiratory parameters. Saliva samples were collected for cortisol analyses each morning and evening across the 4 days of the study. Psychological disturbances were assessed with the SCL. Results: Patients reported significantly more dissatisfaction with their sleep quality and increased daytime fatigue as a result of both insomnia-type symptomatology and nonrestful sleep. These complaints were significantly greater in IBS+D compared to IBS-only for some measures. A significant proportion of patients, particularly IBS+D patients, reported nighttime GI symptoms. Patients reported significantly greater average anxiety across the 4 days, which was greatest in IBS+D. Although both patient subgroups showed normal levels and circadian changes in cortisol compared to controls, IBS+D had significantly increased morning salivary cortisol levels compared to IBS-only. PSG data showed no significant differences between the patient groups and controls. Significant correlations were found between psychological distress and retrospective subjective sleep complaints for patients. Conclusions: This study confirms the importance of sleep complaints and nighttime GI symptoms in women with IBS that are not substantiated by any objective, physiological evidence. Rather, there is a reporting bias regarding sleep disturbances, which appears to be related to symptom severity and psychological disturbances.