Irritable Bowel Syndrome (IBS): Causes, Triggers and Treatments

Irritable Bowel Syndrome, also known as IBS, is a chronic disorder of the gastrointestinal tract that affects the stomach and intestines, the Mayo Clinic reports. The symptoms can range from mild to severe, including abdominal pain, bloating, gas, diarrhea, constipation and cramping.

IBS is a syndrome (a cluster of several symptoms), and signs can differ depending on the person, Lisa Ganjhu, a gastroenterologist at NYU Langone Health, says. It's a condition that needs to be managed long-term.

The American College of Gastroenterology estimates that 10% to 15% of adults have IBS, yet just 5% to 7% have been diagnosed. Nearly twice as many women as men have IBS.

IBS and IBD (Inflammatory Bowel Disease) are different conditions and are often confused. "IBD is an inflammatory condition of the gastrointestinal tract," Ganjhu explains. Crohn's Disease and Ulcerative Colitis are examples of IBD. "They are systemic conditions and can have extra gastrointestinal manifestations," Ganjhu adds.

"Crohn's and Colitis are associated with inflammation in the lining of the gut [gastrointestinal system] that can be seen or biopsied," says Kyle Staller, director of the GI Motility Lab at Massachusetts General Hospital.

However, IBS usually has no visible inflammation, and people who have IBD can also have IBS.

Ganjhu reports that since IBS has no cure, lifelong management and trigger avoidance are essential. Risk factors include being female and under 50, underlying depression, anxiety, or PTSD (Post Traumatic Stress Disorder), being a survivor of sexual abuse, and travelers' diarrhea/prolonged gastroenteritis.

"Data suggests that early life trauma, which can include physical, sexual or emotional abuse, is a real risk factor for IBS," Staller explains. "These types of trauma likely change the way the brain and the gut communicate with each other and increase the risk for IBS." However, most people with IBS don't have a history of traumatic childhoods.

Prevention of IBS is less of a factor than in other conditions. "Although we would like to think that IBS is something that we can somehow avoid, some of the most common risk factors are unavoidable," Staller explains.

"Genetics is also thought to play a role, and we frequently see IBS in multiple generations of a family— though the culprit genes are not entirely known," he adds.

Staller explains having a gastrointestinal bug or infection is a notable risk factor. "Those at increased risk of IBS for some of the risk factors can be more susceptible to developing IBS after a bout with a GI bug."

Several triggers can cause IBS flareups: stress, food intolerances, sensitivities, spicy food, fatty food, caffeine and fiber. "Anything that may alter gastrointestinal motility [the movement of food through the GI system] can trigger a flareup. So lifestyle interventions include stress management and trigger management," Ganjhu says.

Ganjhu suggests several "rescue therapies" that work when treating IBS: "Lifestyle interventions include medications based on symptom management, antispasmodics for pain and cramping, fiber and laxatives for constipation, and antidiarrheal medications for diarrhea."

According to Staller, "There is no one-size-fits-all treatment for IBS." Instead, treatment depends on choosing effective strategies and determining the patient's comfort. 

In addition to fiber supplements and trigger avoidance for mild IBS, other therapies include medications to slow down or speed up gut motility, and drugs and antidepressants called neuromodulators that change the function of the brain-gut axis.

Adopting a low-FODMAP elimination diet (reducing some types of carbohydrates) can also be helpful.

"IBS is a classic biopsychosocial disease: that is, there are biological mechanisms (including changes in gut motility, sensation and dietary intolerances) as well as psychosocial factors where stress and life events can turn up the volume in symptoms in someone with these risk factors," Staller explains. "The best way to think about IBS is as a disorder of gut-brain interaction. When the communication between the brain and gut is altered, people are at risk for IBS symptoms."

Psychotherapy or counseling can help, especially cognitive behavioral therapy (CBT). "There is strong evidence that CBT can be a very powerful tool in our arsenal for treating IBS," Staller says. 

"CBT allows IBS patients to recognize when certain situations or thoughts trigger IBS symptoms and teaches them to use specific techniques to quiet those symptoms."

Some research suggests that hypnotherapy can be effective. "Gut-directed hypnotherapy – not just any old hypnotherapy but hypnotherapy specifically designed for treating those with disorders of gut-brain interaction like IBS," Staller says.

While most people with IBS develop it before age 30, IBS can continue beyond 50. So if you're over 50, you should see a GI doctor to rule out other causes of your symptoms. 

For example, while a colonoscopy cannot diagnose IBS, it can ensure nothing else is happening in your intestines. "Most of the time IBS starts in youth and can progress through a lifetime with system flaring and resolving depending on triggers," Ganjhu says. "When symptoms develop later in life, we are concerned with malignancy causing those symptoms."

"If someone has reached 50 or 60 having never had sensitivity or problems with their gut, it is less likely that IBS is causing symptoms," Staller notes. "As we age – particularly above 50 – it becomes less likely that brand new gut symptoms are due to IBS and more likely that they are due to something else like inflammation or something structurally wrong."

When treating older patients with IBS, there are some things to remember. "Like the case for many diseases, if using medications to treat IBS, we should be aware of increased risk for certain side effects (including effects on cognitive function) that is higher in older people," Staller says. 

"The first and most important step in treating older people with IBS is to make sure they are up to date with their colon cancer screening."

What's the future of IBS treatment? Staller suggests new IBS-specific medications and apps that directly bring CBT, gut hypnotherapy and dietary guidance to patients, although choosing the right one can be problematic. He also anticipates future IBS treatments that target the gut microbiome.

Staller reports that while certain probiotics may be beneficial, "the lack of powerful effects is probably more about our lack of understanding of how gut bacteria play a role in IBS (and therefore which probiotic to use in which person) rather than saying probiotics altogether won't be useful."