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Digestive Problems in ‘Long COVID’ Linked to Psychological Trauma, According to OU College of Medicine Research

William M. Tierney smiling in his doctor's coat, standing in the OKC skywalk.

Digestive Problems in ‘Long COVID’ Linked to Psychological Trauma, According to OU College of Medicine Research

March 15, 2024

OKLAHOMA CITY, OK — Many people who were hospitalized with COVID-19 when the virus arrived in spring 2020 experienced a high rate of gastrointestinal problems and psychological trauma more than a year later, according to a recently published study led in Oklahoma by the University of Oklahoma College of Medicine. The research highlights the powerful relationship between the intestines and the brain, as well as a continued understanding of “long COVID” symptoms.

Gastroenterologist and Professor of Medicine William Tierney, M.D., led OU College of Medicine’s participation in the study, which included hundreds of patients at academic health centers across North America. The study appears in the journal Clinical Gastroenterology and Hepatology.

“Gastroenterologists don’t often ask our patients if they have had COVID-19, but this study provides clear evidence that prior COVID infection can lead to long-term gastrointestinal symptoms,” Tierney said. “I think the main takeaway from this research is that primary care physicians and digestive disease specialists need to remember that COVID could be the trigger for a patient’s long-term digestive symptoms. This notion can help provide an understanding of patients’ symptoms and potentially avoid unnecessary testing.”

In the study, more than 60% of participants met the criteria for DGBI, or Diseases of the Gut-Brain Interaction. DGBIs are believed to be caused by impaired communication between the brain and the gut (intestines) via the nervous system in both directions (brain to gut and gut to brain). With DGBIs, patients experience gastrointestinal symptoms, but tests don’t identify inflammation or other intestinal diseases. The 60% rate of DGBIs in the study far exceeds what gastroenterologists see in a general population of patients.

The most common symptoms that patients experienced more than a year after their COVID-19 diagnosis were dyspepsia (upset stomach), irritable bowel syndrome, diarrhea, constipation and dysphasia (a sense of abnormal swallowing). When study participants were initially hospitalized with COVID-19, about half had similar digestive problems, but the fact that the symptoms have not only endured but have increased in frequency is significant, Tierney said.

In addition, the study revealed that more than 40% of participants met the criteria for Post-Traumatic Stress Disorder, or PTSD, which was a significant and unexpected finding, Tierney said. Notably, the research established a link between patients meeting the criteria for PTSD and experiencing long-term gastrointestinal symptoms.

“Obviously, the early months of the pandemic were very fearful and traumatic, but it is significant that patients were still experiencing trauma more than a year after they were hospitalized,” he said. “However, because other symptoms of long COVID are neurological — such as brain fog and depression — it’s not surprising that DGBIs are among the long-term symptoms. COVID-19 is primarily a respiratory illness, but other respiratory conditions such as the flu typically don’t cause long-term gastrointestinal issues, so it’s clear that COVID-19 is different.”

The OU College of Medicine is one of 36 academic health centers in North America that formed the North American Alliance for the Study of Digestive Manifestations of COVID-19. The group has published several other research studies involving more than 1,500 patients.

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April Wilkerson

About the University of Oklahoma

Founded in 1890, the University of Oklahoma is a public research university located in Norman, Oklahoma. As the state’s flagship university, OU serves the educational, cultural, economic and health care needs of the state, region and nation. OU was named the state’s highest-ranking university in U.S. News & World Report’s most recent Best Colleges list. For more information about the university, visit

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