Prevalence of irritable bowel syndrome in chronic fatigue.

The aetiologies of irritable bowel syndrome and chronic fatigue are unknown. Psychological as well as physical factors have been implicated in both. Fatigue is common in irritable bowel syndrome patients. The purpose of the study was to determine the prevalence of irritable bowel syndrome in chronic fatigue sufferers. A bowel symptom questionnaire was sent to all 4,000 members of a self-help group for fatigue sufferers. Of the 1,797 who responded, 1,129 (63%) fulfilled a diagnosis of irritable bowel syndrome (recurrent abdominal pain and at least three Manning criteria). This greatly exceeds estimates of irritable bowel syndrome prevalence of up to 22% in the general population. Furthermore, irritable bowel syndrome sufferers within this chronic fatigue population reported more Manning criteria (14% had all six Manning criteria) than irritable bowel syndrome sufferers in the general population. This study demonstrates an overlap of symptoms in chronic fatigue and irritable bowel syndrome. In chronic fatigue, irritable bowel symptoms may be one aspect of a more generalised disorder.

Central 5-hydroxytryptaminergic function in irritable bowel syndrome.

BACKGROUND: Psychological factors may contribute to the aetiology and exacerbation of symptoms in irritable bowel syndrome (IBS), suggesting that the central nervous system may be an important site of dysfunction in IBS. Hormonal responses after a serotonergic challenge assess the functional integrity of central 5-hydroxytryptaminergic pathways and are diminished in depression. The aim of this study was to determine whether hormonal responses in IBS after a serotonergic challenge would be decreased, as in depression, or exaggerated, as have been reported in another functional gastrointestinal disorder, nonulcer dyspepsia. METHODS: Fourteen IBS patients, 16 healthy volunteers, and 9 patients with inflammatory bowel disease were given 30 mg d-fenfluramine, a selective stimulus to central 5-hydroxytryptaminergic pathways. RESULTS: Plasma prolactin and cortisol concentrations during the following 5 h increased to a similar extent in all three subject groups, despite increased levels of anxiety and depression (as scored on the Hospital Anxiety and Depression Scale and Beck Depression Inventory) in the IBS and inflammatory bowel disease patients compared with the healthy controls. Base-line cortisol concentration correlated with the magnitude of affective disorder. CONCLUSION: In contrast to the alterations of central 5-hydroxytryptamine receptor sensitivity seen in depression and non-ulcer dyspepsia, central 5-hydroxytryptaminergic pathways function normally in IBS.

Selective affective biasing in recognition memory in the irritable bowel syndrome.

The cognitive model of depression assigns a central role to negatively biased information processing in the pathogenesis of the emotional disorder. The relationship between depression and irritable bowel syndrome (IBS) was explored from a cognitive perspective. A word recognition memory task was constructed: subjects had to memorize and subsequently recognise a set of emotionally loaded stimulus words with either positive, neutral, or negative connotations. Four age matched groups participated--30 IBS patients, 28 depressed patients, 28 patients with organic gastrointestinal disease, and 30 healthy volunteers. The depressed patients, as would be expected, showed a significant bias in favour of emotionally negative words (p < 0.05): the IBS patients showed the same negative bias. In addition the IBS patients made significantly more false-positive type errors in recognising emotionally negative words than either the depressed patients (p < 0.05) or the healthy volunteers (p < 0.01). This suggests that the IBS patients have a peculiar confirmatory bias for negative material. This may have clinical relevance in terms of the IBS patients' evaluation of their own abdominal sensory experience.