Irritable bowel syndrome (IBS) is a gastrointestinal disorder that affects the small and large intestines, causing symptoms like abdominal pain, bloating, constipation, and diarrhea.IBS occurs when there is a disconnect between your brain and digestive tract, leading to increased sensitivity in your gut. It neither causes permanent damage to your digestive tract nor increases your risk for colorectal cancer — unlike inflammatory bowel disease (IBD), which is sometimes confused with IBS but is an entirely different disorder. Still, IBS can be frustrating and even debilitating at times, affecting your physical, emotional, and social well-being.

Types of Irritable Bowel Syndrome

Your doctor may classify your IBS on the types of abnormal stool you may have. These include:

• IBS with diarrhea (IBS-D), which may involve loose, watery stools

• IBS with constipation (IBS-C), which may involve stools that are lumpy and hard

• IBS with mixed bowel habits (IBS-M), which includes diarrhea and constipation symptoms

Signs and Symptoms of Irritable Bowel Syndrome

IBS symptoms are not always consistent. They can appear and disappear, and they depend on the type of IBS you have. Symptoms may include:

• Abdominal pain or cramping

• Bloating and excess gas

• Diarrhea or constipation or alternating bouts of each

• Large amounts of whitish mucus in your stool

• Feeling unable to empty your bowels

Causes and Risk Factors of Irritable Bowel Syndrome

Researchers don’t know exactly why some people get IBS. But they speculate that stress in early life may play a role, as do changes in microbes and nerve issues in your gut.

The brain and gut are connected and communicate through a network of nerves that line your gastrointestinal tract. This grouping is called the enteric nervous system, and it controls digestion and tells the bowels when to contract, move, and secrete fluids.A stress response in your gut can cause symptoms elsewhere, and vice versa, says Judith Scheman, PhD, director of behavioral medicine at Cleveland Clinic’s Digestive Disease and Surgery Institute in Ohio. In fact, IBS may be more genetically similar to psychiatric disorders than gastrointestinal ones, according to research.

“When we describe our emotions, we tend to say that we feel sickened or nauseated, or [it is] gut-wrenching, which makes sense since our emotions seem to occur from our gut,” Dr. Scheman says. “We all respond to stress physically, and some of us physically react with our gut, as with diarrhea or constipation, while others get headaches or back pain,” Scheman says.

Other potential factors that may lead to IBS include:

• Viral or Bacterial Infections These may affect your gastrointestinal tract and the “wiring” of your GI system even after the infection is resolved. Some conditions also may cause postinfectious IBS, or IBS-like symptoms that appear after the infection itself has gone away. For most people, post-infectious IBS is temporary, but symptoms can last from several weeks to years.

• Muscle Contractions If your colon muscle contracts more than normal, it may lead to IBS, cramping, and pain. Weaker contractions can lead to dry, hard stool.

• Gut Bacteria Research has shown that gut bacteria in people with IBS is different than in people without it, though more research is needed to understand this further.

• Food Allergies Sensitivity to certain foods may cause IBS symptoms in some people.

Risk Factors for IBS

A number of different factors may increase your risk of developing IBS. These include:

• Age IBS can strike at any age, but people younger than 50 are more likely to develop it.

• Family History Genetic factors or those related to a shared environment may come into play.

• Sex Women are more likely to develop IBS than men. This may be because of sex hormones, particularly estrogen and progesterone, may influence gut function and sensitivity.

• Depression and Anxiety Mood disorders and IBS may be linked, says Jeffrey Baumgardner, MD, a gastroenterologist in Santa Rosa, California. “A significant number of people with IBS also have a history of some kind of abuse — emotional, physical, or sexual,” he says. Gastrointestinal issues also may fuel depression and stress.

Just as IBS varies from person to person, different factors can trigger IBS symptoms. These triggers include:

• Foods or Food Ingredients These may include milk and dairy products, citrus, cabbage, wheat, and carbonated beverages.

• Stress Perhaps not as a direct cause, but stress may aggravate IBS symptoms.

How Is Irritable Bowel Syndrome Diagnosed?

Your doctor will try to diagnose you based on your symptoms. You may receive questions about the onset and frequency of your symptoms, any recent illnesses, and your medication history. Criteria for IBS may include pain and discomfort at least once a week for three months as well as:

• Pain in bowel movements

• Change in bowel habits

• Change in stool consistency

Depending on your symptoms and risk factors, your doctor may perform tests, such as blood or stool tests, to rule out serious conditions like celiac disease, IBD, and colon cancer. At times your doctor may order an upper endoscopy or colonoscopy as well.

Treatment Options for Irritable Bowel Syndrome

There’s no one-size-fits-all treatment for IBS. Most people with IBS try different treatments before they find one or more that work.

Dietary Changes

Your doctor may suggest dietary changes before other types of treatment for IBS. These may include increasing your fiber intake through food or supplements and staying away from foods that may be triggers.

Figuring out which foods cause IBS symptoms can be tricky, however. Consider keeping a food diary to help you identify foods that may be triggers.

A low-FODMAP diet can also help ease symptoms for some people. FODMAP stands for “fermentable oligosaccharides, disaccharides, monosaccharides, and polyols,” which are poorly digested carbohydrates that can cause gas, bloating, and diarrhea. Reducing these requires cutting down on dairy, fruit, some vegetables, beans, and sugar-free sweeteners. This is meant to be temporary to identify food triggers. Working with a dietician is key to reintroduce foods; there are also modified versions of the low-FODMAP diet that may be less restrictive.Other diets that cut carbohydrates in favor of proteins and fats have reduced symptoms for a majority of people with IBS.

Talk to your doctor or a registered dietician before making any dietary changes. Some diets are restrictive and may leave you without necessary nutrients, while others may not be appropriate for your situation.

Medications

Medications for IBS with diarrhea include:

• Loperamide (Imodium) “Even though loperamide hasn’t been well-studied in relation to IBS, it works well for diarrhea,” says Anthony Lembo, MD, of Cleveland Clinic's Digestive Disease and Surgery Institute in Ohio.

• Eluxadoline (Viberzi) This reduces muscle contractions and fluid in the intestine and can slow down an overactive bowel. Possible side effects include stomach pain, allergic reactions, and constipation.

• Rifaximin (Xifaxan) A gut-selective antibiotic, this reduces diarrhea, abdominal pain, and bloating. The drug is given as a two-week course and may need to be repeated.

• Alosetron (Lotronex) This blocks the action of serotonin on the intestine, which helps reduce cramping, abdominal pain and discomfort, diarrhea, and the sudden need for a bowel movement. One of the more common side effects is constipation. This is only prescribed for women with severe IBS-D.

• Bile Acid Binder Your doctor may recommend cholestyramine (Prevalite), colestipol (Colestid), or colesevelam (Welchol) if excess bile is irritating your colon. This medication may cause bloating.

If you have IBS with constipation, medications may include:

• Laxatives These hold more water in your bowel to soften stool, making it easier to have a bowel movement.

• Lubiprostone (Amitiza), plecanatide (Trulance), and linaclotide (Linzess) These medications increase fluid secretion in your small intestine to help you pass stool. Side effects may include nausea and dizziness. Some may be prescribed only to women with severe IBS-C.

• Tenapanor (Isbrela) This increases water retention, which can lead to more frequent and softer bowel movements. It may be prescribed after another first-line treatment has failed. Side effects include diarrhea, flatulence, and dizziness.

Your doctor also may prescribe low doses of tricyclic antidepressants (TCAs) and antispasmodics if you are having pain with IBS. Some also may suggest antidepressants known as selective serotonin reuptake inhibitors for IBS, especially if you can’t tolerate TCAs and experience depression.

Complementary and Integrative Therapies

If you are consuming too little fiber, your doctor may recommend soluble fiber supplements. Fiber can make bulky stool easier to pass, decreasing your chance of constipation, but it can also solidify stool, providing relief from diarrhea. Still, be aware that consuming too much fiber is a real problem that can bring on bouts of bloating, gas, and other IBS symptoms.Other potential options for easing IBS symptoms may include:

• Peppermint Oil Peppermint contains L-menthol, which can help reduce painful spasms in the digestive tract.

• Probiotics Evidence is mixed on their efficacy, however.

• Cognitive Behavioral Therapy (CBT) This form of psychotherapy focuses on symptom-related worry. CBT targets the brain-gut connection, a key contributor to IBS symptoms.

• Gut-Directed Hypnotherapy This therapy aims to alter your body’s responses to IBS symptoms by making your gut react less to emotional upheaval and stress and changing how the brain interprets signals from the gut.

Lifestyle Changes and Prevention of Irritable Bowel Syndrome

Dr. Lembo, who is an author of the American Gastroenterological Association’s guidelines for IBS treatment, recommends making lifestyle changes before trying medications and other therapies to manage your IBS symptoms.

Research has shown that certain lifestyle factors may reduce your risk of having IBS, including:

• Not smoking

• Getting at least seven hours of sleep every night

• High levels of vigorous exercise

• Eating a balanced diet daily

• Limiting alcohol use to one drink a day or less

“These factors can significantly reduce your risk of developing IBS, especially if you do multiple of these factors,” Lembo says. “And there are other benefits from these factors as well, like cutting the stress and the risk of heart disease.”