Few digestive diseases are as widely experienced and as difficult to live with than irritable bowel syndrome, also known as IBS. But for patients seeking respite from painful digestive symptoms like cramping, pain, bloating, gas, diarrhea and constipation, their diagnosis can sometimes bring more questions than answers.

Irritable bowel syndrome, or IBS, is a multifaceted, highly individualized diagnosis given when a set of symptoms cannot be adequately explained by another disease or structural problem, like an inflammation, infection, or cancer. This can be deeply frustrating for patients, who sometimes undergo many diagnostic tests, including blood tests, endoscopy, and physical examinations, only to be told that there is nothing wrong with their intestines. But the truth is much more complicated.

Ira Hanan, MD, gastroenterologist and professor of medicine at the University of Chicago Medicine Digestive Diseases Center, and an expert in treating IBS, explains it this way: “If you looked at a car, and you could see that the car had a flat tire, you could understand that there was something physically wrong with the car, and could work to fix it. But if everything looks normal on the car, and for some reason the car isn’t working, that’s a functional problem, as if the car didn’t have gas or the fuel pump was not working properly. It doesn’t mean that the car is in good working order.”

IBS is a common digestive concern, affecting 10 to 20 percent of the general population, though only 15 percent of those individuals seek treatment for their symptoms. The cause is unknown, though theories range from an imbalance in the gut microbiome, to sensitivity to food additives, to visceral hyperalgesia, a term meaning that intestines are hypersensitive to the normal movements of the bowel, causing pain and discomfort.

“Dr. Kirsner always referred to the gut having it’s own neurologic system. While we think of our neurologic system as being our brains, along with the nerves that leave our brain and go through our body, Dr. Kirsner always used to say that the intestine has it’s own internal nervous system, and sometimes the way that it contracts and relaxes causes problems for the patient,” explains Hanan.

Effective treatment of IBS first involves listening to the patient, and reassuring them that their symptoms are very real, and not all in their heads. There is no surgical treatment of IBS, but many classes of medications can help IBS sufferers find symptomatic relief.

“Irritable bowl is an entire spectrum,” explains Hanan. “Treatment must be tailored to the patient… because one person’s IBS can be 180 degrees from another’s.”

“It’s not necessarily a glamorous disease,” explains Hanan, “but fifteen years ago, you couldn’t find an FDA approved medication for irritable bowel syndrome, because it didn’t exist.”

Different medications are used to treat the different classes of IBS: IBS-D (primarily diarrhea), IBS-C (primarily constipation), or IBS-M (for mixed symptoms). Medications include anticholinergic medications (those that block the nervous system’s stimulation of the GI tract); antidepressants, which may reduce pain perception; antidiarrheal drugs; antibiotics; and medications that increase intestinal lubrication to prevent constipation. Physicians also recommend that patients examine their diets using techniques like the elimination diet to better understand the way that what they eat may interact with their symptoms.

Not that long ago, a person with IBS might have struggled to get a diagnosis, let alone relief from their symptoms. Now, with the hope of research for new diagnostic approaches and more effective treatments, there is promise for improvement of the quality of life for millions with IBS.