Increased colonic pain sensitivity in irritable bowel syndrome is the result of an increased tendency to report pain rather than increased neurosensory sensitivity.

OBJECTIVE: The aim was to determine whether lower visceral pain thresholds in irritable bowel syndrome (IBS) primarily reflect physiological or psychological factors. METHODS: Firstly, 121 IBS patients and 28 controls underwent balloon distensions in the descending colon using the ascending methods of limits (AML) to assess pain and urge thresholds. Secondly, sensory decision theory analysis was used to separate physiological from psychological components of perception: neurosensory sensitivity (p(A)) was measured by the ability to discriminate between 30 mm Hg vs 34 mm Hg distensions; psychological influences were measured by the report criterion-that is, the overall tendency to report pain, indexed by the median intensity rating for all distensions, independent of intensity. Psychological symptoms were assessed using the Brief Symptom Inventory (BSI). RESULTS: IBS patients had lower AML pain thresholds (median: 28 mm Hg vs 40 mm Hg; p<0.001), but similar neurosensory sensitivity (median p(A): 0.5 vs 0.5; p = 0.69; 42.6% vs 42.9% were able to discriminate between the stimuli better than chance) and a greater tendency to report pain (median report criterion: 4.0 ("mild" pain) vs 5.2 ("weak" pain); p = 0.003). AML pain thresholds were not correlated with neurosensory sensitivity (r = -0.13; p = 0.14), but were strongly correlated with report criterion (r = 0.67; p<0.0001). Report criterion was inversely correlated with BSI somatisation (r = -0.26; p = 0.001) and BSI global score (r = -0.18; p = 0.035). Similar results were seen for the non-painful sensation of urgency. CONCLUSION: Increased colonic sensitivity in IBS is strongly influenced by a psychological tendency to report pain and urge rather than increased neurosensory sensitivity.

Functional gastrointestinal disorders: an update for the psychiatrist.

Functional gastrointestinal disorders (FGID) are common conditions, with well-established diagnostic criteria. They are associated with impaired health-related quality of life and increased societal and healthcare costs. Their symptoms are probably related to altered 5-HT transmission and central processing of noxious visceral stimuli. Evaluation and treatment are best formulated using a biopsychosocial model that integrates gut function with psychosocial assessment. Psychological therapies may improve overall well-being and appear to help patients without significant psychiatric comorbidity. Antidepressants help comorbid anxiety and depressive disorders and have primary efficacy in improving the symptoms of FGID. Finally, there is a need for greater involvement of psychiatrists in both the evaluation and treatment of patients with FGID as well as the education and training of practitioners caring for these patients.

Psychosocial assessment of functional gastrointestinal disorders in clinical practice.

Functional gastrointestinal disorders are the most common conditions encountered in gastroenterology practice and are also commonly encountered in primary care. Psychosocial factors play an important role in these disorders (along with any chronic digestive disorder) by influencing healthcare seeking, illness behavior, symptom severity, quality of life, and digestive motility and sensation. Identification of relevant psychosocial factors in patients with chronic digestive disorders influences care and is a critical determinant of outcomes. This article provides a review of relevant psychosocial variables, assessment techniques, and therapeutic suggestions that can be of value in assessing patients with functional gastrointestinal disorders.

Cilansetron.

Irritable bowel syndrome is an extremely common disorder affecting approximately 10-20% of the population of North America and Europe. This disorder is characterized by abdominal pain and altered bowel habit. The altered bowel habit can take a number of forms. These include a predominant diarrhea form, a form with constipation and one in which patients alternate between diarrhea and constipated forms of the disorder. Irritable bowel syndrome to date has not been associated with any excess mortality. However, the morbidity associated with irritable bowel syndrome is quite high. This mainly takes on the form of impairment in health-related quality of life, interference with activities of daily living and a considerable degree of human suffering. Likewise, the economic impact of irritable bowel syndrome is not trivial and has been estimated to be between US$20 to 30 billion in the United States alone. In an effort to address this common disabling disorder, a number of new drugs have been developed. One of the latest is cilansetron, which is a competitive type 3 serotonin (5-HT3) receptor antagonist. In phase III trials, cilansetron has been shown to be efficacious for the relief of a wide spectrum of symptoms related to irritable bowel syndrome with diarrhea both in male and female patients. By and large, cilansetron is extremely well tolerated and highly efficacious. The most common side effect of cilansetron is constipation, which is seen in 3-12% of subjects at 6 months. Ischemic colitis, a side effect associated with previous drugs of this class, has been seen in eight subjects (six women and two men) to date. All of these ischemic colitis events have been self-limited and did not require surgery. Because of its high degree of efficacy, the fact that it is well tolerated by the overwhelming majority of patients and that it shows efficacy in both genders, cilansetron represents a major advance in the treatment of irritable bowel syndrome with diarrhea predominance.