BRIAN LACY, MD: Irritable bowel syndrome is a chronic disorder that affects the nervous system to the gut. It's incredibly common; it affects approximately one in five adult Americans.
SUSAN LUCAK, MD: It is a disorder that's characterized by abdominal pain or discomfort, associated with bowel irregularities, such as diarrhea or constipation or alternating constipation with diarrhea in the same patient.
LIN CHANG, MD: Other common symptoms are bloating, sensation of incomplete evacuation -- the patient never feels like they evacuate their stool completely -- urgency, particularly in patients with diarrhea, and sometimes mucus in the stool.
SUSAN LUCAK, MD: Patients with irritable bowel syndrome have various severities. Approximately 70 percent of patients with irritable bowel syndrome will have mild symptoms. Approximately 25 percent of patients have more moderate symptoms; that is, they have symptoms that may interfere with their functioning. And approximately 5 percent have very severe symptoms where they may be disabled.
ANNOUNCER: For many people, IBS brings pain and discomfort. For some, it can be extremely disabling.
LIN CHANG, MD: They have difficulty getting up in the morning and going to work because they're having pain, or they have to use the bathroom multiple times. And that's not only with patients with diarrhea, but it's also patients with constipation, where they feel like they need to evacuate. They can't leave their house. Or they're at work and they have to rush and find a bathroom. And specifically in patients with severe diarrhea, they have to worry about incontinence or losing control of their stool, which can be one of the most humiliating and embarrassing experiences.
ANNOUNCER: A majority of people with IBS are women, although the reason why is unknown.
SUSAN LUCAK, MD: Generally, irritable bowel syndrome is a disorder of young women. The onset is generally in their 20s and 30s and it tends to persist in an intermittent way throughout life. And it seems that around the age of 59 or 60, studies have shown that there is a diminution of symptoms of irritable bowel syndrome.
ANNOUNCER: Research has shed light on factors that may contribute to the development of IBS.
BRIAN LACY, MD: Several good studies over the last few years have shown that there may be a genetic predisposition to develop irritable bowel syndrome.
However, most of us in the field also believe that that's not enough. That there probably has to be a second insult or a second injury that may then trigger the irritable bowel syndrome or bring it to the forefront.
ANNOUNCER: Research has also shown an association between prior infections and IBS.
LIN CHANG, MD: Anywhere between 7 and 30 percent of individuals with IBS will report that they had previous proven bacterial gastroenteritis. That can change the immunologic function of the lining of the gut. That may be related to their symptoms of, for example, pain and diarrhea.
ANNOUNCER: The exact cause of IBS remains unknown, and for most IBS patients, no predisposing factor can be identified. However, doctors have learned much about the factors associated with the symptoms of IBS.
LIN CHANG, MD: One is altered gut motility or gut motor function, where the motility of the lower bowel will not be normal. It will either be too fast where a stool passes too quickly, or it will be too slow, where a stool passes much more slowly, and patients will develop diarrhea or constipation.
The second one is enhanced gut sensitivity, where the patients will be more sensitive to contents of the gut, such as stool or gas. So they'll feel bloated or they'll feel pain or discomfort.
The third factor is communication between the brain and the gut. That's important for general gut function. If there is any disregulation in the brain/gut interactions, you will have changes in bowel function.
ANNOUNCER: Because the brain communicates with the intestines, emotions and stress can contribute to flare-ups of bowel disorders.
SUSAN LUCAK, MD: Psychological factors do not cause irritable bowel syndrome. But they may aggravate the symptoms of irritable bowel syndrome. For instance, depression, anxiety, obsessive-compulsive disorder and other psychological disturbances may worsen the symptoms of irritable bowel syndrome.
ANNOUNCER: While the causes of IBS remain unknown, doctors can provide a great deal of help. In fact, one of their key messages to people suffering from gastrointestinal disorders is: don't try to go it alone.
BRIAN LACY, MD: As a physician, one of the frustrating things I find about IBS is that oftentimes many patients with chronic symptoms don't see a doctor. And I think that we need to educate patients better about that to get them to come in so we can reassure them. And to let them know there are now medications available that can improve their symptoms and improve their quality of life.