Researchers Explore Genetic Links Between IBS and Mental Health Conditions

For years, researchers have been looking at how brain and gut health are connected. Now, a new study has found another connection between the two.

The study showed that because they share certain genetic pathways, people with irritable bowel syndrome (IBS) tend to be more likely to develop certain mental health conditions—particularly anxiety disorders.

For many people with IBS, treating anxiety is a crucial component of helping them manage their IBS symptoms effectively.

The study, which was published in the journal Nature Genetics, analyzed genomic data from 53,400 people with irritable bowel syndrome (IBS) and compared them to 433,201 people without IBS.

The findings were repeated using de-identified data from 23andMe (which was provided by customers who consented to research) that compared 205,252 people with IBS to 1,384,055 controls.

The researchers found that a person’s genes are not a large predictor of how likely they are to develop IBS. The researchers concluded that environmental factors like diet, stress levels, and behavioral patterns within families could lead to IBS.

However, the researchers did identify six genetic differences that were more common in people with IBS than in controls. The genes that the researchers noted differences in (NCAM1, CADM2, PHF2/FAM120A, DOCK9, CKAP2/TPTE2P3, and BAG6) have more obvious roles in the brain and nerves than the gut.

Shared Genetic Pathways

When the researchers looked for overlap between a person’s likelihood of developing IBS and their risk for other mental health conditions, they discovered that the genetic changes that put someone at an increased risk for IBS also increased their risk for certain mental health conditions such as anxiety, depression, neuroticism, and insomnia.

The researchers acknowledged that the study's findings do not mean that anxiety causes IBS—or vice versa. Rather, they concluded that IBS and certain mental health conditions have “shared genetic pathways” and that the study's findings “require further exploration to help understand the altered brain-gut interactions underlying IBS.”

IBS Basics

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder—one that involves gut-brain interactions and is related to how your brain and gut work together.

If your brain and your gut are not communicating properly, it can cause your gut to become more sensitive or even change how the muscles in your bowel contract. These changes can affect bowel function and lead to diarrhea, constipation, or both (mixed-type IBS).

These symptoms can make you feel like you have not finished a bowel movement, and produce whitish mucus in your stool.

Doctors are not sure what causes IBS but certain factors are common in people with the condition, including stressful or difficult early life events, physical or sexual abuse, certain mental health disorders like depression and anxiety, bacterial infections in the digestive tract, bacteria in the small intestine, and food intolerances or sensitivities.

Anxiety Basics

Anxiety is a feeling of fear, dread, and uneasiness that can lead to tension and a rapid heartbeat. While anxiety can be a normal reaction to stress, people can develop anxiety disorders, which are when you have anxiety that does not go away and may worsen over time.

The symptoms of anxiety disorders can interfere with a person’s daily activities, making it difficult for them to perform at work and school.

People who are diagnosed with anxiety disorders can experience anxious thoughts or beliefs that are hard to control, physical symptoms (such as a pounding or rapid heartbeat, dizziness, and shortness of breath), and changes in behavior (like avoiding activities that you used to do).

What Doctors Think

The study's findings did not come as a shock to many health care professionals. Ashkan Farhadi, MD, a gastroenterologist at MemorialCare Orange Coast Medical Center in Fountain Valley, Calif., told Verywell that "makes a lot of sense" because "we know that the gut and brain are connected, and the GI tract is an abundant place in the body for neurotransmitters and neurons of the central nervous system. It’s a no-brainer that anxiety aggravates IBS and vice versa.”

Anjali Pandit, PhD, a clinical health psychologist who specializes in the care of patients with gastrointestinal issues at Northwestern Medicine, told Verywell that there has been an “evolution” in understanding anxiety and IBS. “Farthest back, and largely discredited, was the assumption that there is a causative relationship between psychology (anxiety) and physiology (IBS)," she added.

However, that's not how the connection is viewed today. Pandit said that "now we operate under a clearer picture with the nervous system playing a driving role in dysregulating the communication pathways between the brain and the gut. This means that the nervous system plays an important role in the development of IBS.”

Pandit said that the new study, “points to a shared genetic predisposition indicating that there may be a deeper explanation for the parallels and co-occurrence that we see in these two conditions.” 

What's more, Pandit said that the study also “sheds more light on the question of nature versus nurture when it comes to the development of IBS co-occurring with anxiety and perhaps decreases some of the stigma that IBS sufferers may face. There is a bit of relief that may come from the understanding that IBS, genetically, looks a lot like anxiety, which is more accepted by society.”

Treating IBS and Anxiety

Clinical psychologist Thea Gallagher, PsyD, an assistant professor at NYU Langone Health and co-host of the Mind in View podcast, told Verywell that treating IBS often involves treating anxiety as well.

“I’ve collaborated with a lot of GI specialists over the years to help treat patients with IBS,” said Gallagher. “There’s often more we can do to around the anxiety than the IBS, and that can help with IBS symptoms as a result.”

That treatment may include slowing the body down with progressive muscle relaxation and the use of cognitive-behavioral therapy (CBT) to try to adjust a patient’s behaviors to minimize anxiety and, consequently, help address their IBS symptoms.

Pandit said that IBS treatment needs to be individualized and that the study's findings do not change that. “The most effective treatment for IBS and anxiety occurring together will likely look different from patient to patient,” said Pandit. “Some people will feel better sooner if they first focus treatment on IBS and others with a focus on anxiety." Or, it could also be the reverse—some people may do better if they work on managing their anxiety first. 

If you have IBS, Farhadi recommended talking to your doctor about your symptoms and working together on developing a treatment plan that addresses your needs.