Are IBD and Depression Connected?

A clinical overlap exists between both conditions, research from Keck Medicine of USC finds — and either illness may trigger the other.

Inflammatory bowel disease (IBD) is a chronic condition involving inflammation of the digestive tract, affecting some 1.6 million Americans. Depression affects more than 16 million Americans.

The two concerns may often be connected.

Patients diagnosed with IBD were nine times more likely to develop depression than the general population, a study from Keck Medicine of USC has found. In addition, patients’ siblings who did not suffer from IBD were almost twice as likely to develop depression.

Conversely, patients with depression were twice as likely to develop IBD, and their siblings without depression were more than one-and-a-half times as likely to develop IBD.

IBD causes constant gastrointestinal symptoms that can be very disruptive to a patient’s life.

Bing Zhang, MD, gastroenterologist, Keck Medicine of USC

“This research reveals a clinical overlap between both conditions, ” says Bing Zhang, MD, a gastroenterologist with Keck Medicine and co-lead author of the study, which was published in the Journal of Gastroenterology and Hepatology.

Dr. Zhang and his fellow researchers analyzed the data of more than 20 million people from Taiwan’s National Health Insurance Research Database that contains comprehensive medical information on more than 99% of Taiwanese residents.

“The finding that people with IBD are more prone to depression makes sense because IBD causes constant gastrointestinal symptoms that can be very disruptive to a patient’s life,” he says.

“And the elevated depression risk among siblings of IBD patients may reflect caregiver fatigue if the siblings have a role in caring for the patient.”

Patients with depression could be prone to IBD

What surprised researchers was that patients with depression were prone to IBD. This discovery may have to do with the “gut-brain axis,” a scientifically established connection between the gastrointestinal system and the central nervous system, which consists of the spinal cord and the brain.

For example, inflammation of the brain — which plays a role in depression — may be linked to the inflammation of the gastrointestinal tract, a hallmark of IBD, Dr. Zhang says.

The researchers are not sure why siblings of patients with depression are more likely to be diagnosed with IBD. There may be a shared genetic susceptibility for either disease that presents differently in family members, Dr. Zhang says.

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