Patients with irritable bowel syndrome (IBS) cannot block pain signals from the gut as easily as those without the gastrointestinal condition, new research suggests.
 
In the study, which was presented at the 22nd United European Gastroenterology Week in Vienna, Austria, functional MRI scans displayed greater activation in the pain-related areas of IBS patients’ brains, suggesting deficiencies in pain-inhibiting mechanisms compared with healthy control subjects. Higher depression scores were also associated with reduced pain inhibition, though higher anxiety scores were not.
 
Each study participant experienced painful rectal distensions induced by a pressure-controlled barostat machine while undergoing functional MRIs. The participants also received sequential intravenous saline, as well as a saline placebo that they believed was an antispasmodic.
 
“Our findings suggest that patients with IBS do not process visceral pain signals in the same way as healthy people, and are unable to suppress pain signals in the brain,” said study author Sigrid Elsenbruch, PhD, in a press release. “The fact that the presence of depression was associated with altered brain responses suggests that depression may contribute to these abnormal pain processes in IBS patients.”
 
Depression and anxiety frequently accompany IBS, as approximately 38% of IBS patients have clinically confirmed depression, while 32% have anxiety. The presence of either condition has formed the basis of the belief that IBS is a psychological disorder, rather than a physical one.
 
“The condition is complex and most likely results from an interplay between psychological and biological factors. In fact, we don’t really know whether anxiety and depression result from having IBS, or whether they contribute to the development or maintenance of symptoms,” Dr. Elsenbruch noted. “In many patients, both possibilities may be true at the same time.”