July 27, 2016
2 min read

Functional GI disorders involve both gut-to-brain, brain-to-gut pathways

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A brain-to-gut pathway originating with psychological symptoms and a distinct gut-to-brain pathway originating with gut symptoms are both involved in patients with functional gastrointestinal disorders like irritable bowel syndrome and functional dyspepsia, according to recent study data.

In two-thirds of these patients, gut mechanisms were the primary drivers of their gastrointestinal and psychological symptoms, researchers concluded.

“We believe these results are really a breakthrough in conceptualizing IBS. The data indicate some patients with IBS have a primary gut disease that may not only explain their gut symptoms but also their psychological distress,” Nicholas J. Talley, MD, faculty of health and medicine, University of Newcastle, Australia, said in a press release.

Nicholas J. Talley

Talley and colleagues surveyed a prospective random population sample of 1,900 individuals from Australia (mean age, 57 years; 53% women) who completed a validated survey in 2012 and a 1-year follow-up survey. Both surveys included the Modified Rome III Questionnaire, the Hospital Anxiety and Depression Scale and the SF-12.

At 1-year follow-up, 6.4% of respondents developed new onset IBS, 7.2% developed functional dyspepsia, and nearly half who had IBS or functional dyspepsia at baseline lost their symptoms.

Participants had a higher risk for developing IBS at 1-year follow-up if they had higher baseline levels of anxiety (OR = 1.31; 95% CI, 1.06-1.61; P = .01) and depression (OR = 1.54; 95% CI, 1.29-1.83; P < .001). Participants also had a higher risk for developing functional dyspepsia at 1-year follow-up if they had higher baseline levels of anxiety (OR = 1.28; 95% CI, 1.05-1.55; P = .01) and depression (OR = 1.55; 95% CI, 1.32-1.83; P < .001). These findings implicate brain–gut interactions in these participants, “but not among those who already had IBS or [functional dyspepsia],” the researchers wrote.

Among participants without higher baseline anxiety and depression, those with IBS at baseline had higher anxiety (mean difference, 0.34; 95% CI, 0.13-0.55; P = .002) and depression (0.81; 95% CI, 0.47-1.15; P < .001) at 1 year, and those with functional dyspepsia at baseline also had higher anxiety (0.38; 95% CI, 0.14-0.63; P = .002) and depression (0.92; 95% CI, 0.57-1.27; P < .001) at 1 year. These patterns were not observed in “those who already had elevated anxiety or depression, implicating primary gut-to-brain pathways operate in a major subset with these disorders.”

Among 215 respondents with a mood disorder at baseline, 30 had a functional gastrointestinal disorder at 1 year, and among 309 respondents with a functional gastrointestinal disorder at baseline, 60 had a mood disorder at 1 year. Hence, a mood disorder preceded a functional gastrointestinal disorder in a third of these participants.

“There are now three studies we have done that have all shown this new gut to brain pathway,” Talley said in the press release. “Targeting the gut is much easier than the brain, and in doing so we may be in reach of relieving not only gut pain but also anxiety and depression that arises from gut disease.” – by Adam Leitenberger

Disclosures: This study was supported by Janssen as an Investigator Initiated Study. The researchers report no relevant financial disclosures.