Many people experience gastrointestinal symptoms such as diarrhea, gas, cramps, heartburn, bloating, and nausea that disrupt their lifestyle. The good news is that these ailments frequently aren’t caused by an illness, according to a newly updated Special Health Report from Harvard Medical School. Often they are functional disorders, triggered by stress or anxiety, saysThe Sensitive GutSpecial Health Report.

Anger, anxiety, sadness, and many other emotions can trigger symptoms in the gut. There is a two-way communication system between the gut and the brain that explains why you stop eating when you’re full (sensory neurons in your gut let your brain know that your stomach is distended), or conversely, why anxiety over this morning’s exam has ruined your appetite (the stress activated your “fight or flight” sympathetic nervous system).

That doesn’t mean, however, that functional GI illnesses such as reflux, functional dyspepsia, irritable bowel syndrome (IBS), constipation, diarrhea, and excessive gas are imagined. Stress can affect movement of the GI tract, cause inflammation, or make you more susceptible to infection. While some patients find relief with behavioral psychotherapy, others are reluctant to accept the idea that their very real physical symptoms are the result of emotional stress. But the gastrointestinal tract is particularly sensitive to emotion often resulting in pain and discomfort. The goal of psychotherapy and stress reduction treatments is to reduce anxiety, encourage healthy behaviors, and help patients cope with their condition.

The gut/brain connection is particularly strong in the disorder known as IBS. Stress is known to stimulate colon spasms in people with IBS. The process is not completely understood, but scientists point out that the intestines are controlled partly by the nervous system. Stress reduction, relaxation training, and counseling have each helped relieve IBS symptoms in some people.