As well as affecting how a person feels mentally, anxiety can also have physical effects. A common physical manifestation of anxiety is stomach upset, including diarrhea or loose stools.

Some people believe that how a person feels can influence the way in which their stomach and intestines behave, potentially causing symptoms that include diarrhea.

Sometimes, diarrhea is a chronic condition for a person. In other cases, it is an acute response to profound anxiety, which means that it occurs once or for a limited time.

In this article, we look at why anxiety can cause diarrhea, the possible association with irritable bowel syndrome (IBS), and how a person can treat diarrhea.

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When a person is anxious, the body releases hormones and chemicals that can lead to diarrhea.

There is a connection between the gut and the brain called the “gut microbiota-brain axis.” This bidirectional network between a person’s brain and the gut microbiota allows the brain to affect gut movement.

According to the Anxiety and Depression Association of America (ADAA), when a person is anxious, the body releases hormones and chemicals. These can enter the digestive tract and disrupt the gut flora, which can result in a chemical imbalance that leads to diarrhea.

A study involving people with IBS with diarrhea (IBS-D) found that the participants who also had anxiety had higher levels of certain inflammatory compounds in the body than those who did not.

Specifically, the researchers found that those with anxiety had higher levels of a compound called interleukin-1 beta. This compound can alter the intestine’s protective barrier, which can cause pain and affect the intestine’s ability to absorb water and sodium. Diarrhea can be the result of these effects.

Another possible explanation for anxiety and its effects on diarrhea is that anxiety alters how the brain processes information from the visceral nerves (those present in the stomach and intestines). According to an article in The Lancet, anxiety may cause the brain to process messages from the stomach as indicating pain or that the intestinal movement needs to speed up.

The result can be gastrointestinal dysfunction that makes the stomach and intestines feel as though they are churning. This dysfunction causes digested food to move along the intestinal tract more quickly, resulting in diarrhea.

IBS-D is a condition that can cause a person to experience the following symptoms routinely:

  • abdominal pain or discomfort
  • bloating
  • frequent diarrhea episodes

Although many doctors do not believe that anxiety is a direct cause of IBS-D, anxiety may worsen a person’s symptoms.

An estimated 75% of people with IBS experience anxiety and depression. Chronic diarrhea not only affects the nutrients that a person’s body absorbs from their food but can also lead to dehydration and fatigue.

Having IBS-D can also worsen a person’s anxiety. They may start to fear that they will have a diarrhea episode in public. This worry can cause them to change their behavior and feel anxious.

If anxiety is the underlying cause of diarrhea, minimizing anxiety may help reduce symptoms.

Examples of treatments and remedies that may help include:

  • Avoiding foods that may contribute to stomach upset: A person should avoid consuming caffeine, spicy foods, and foods containing lactose.
  • Psychotherapy: Talk therapy can help a person identify anxiety and learn techniques to manage and reduce it. Therapists may use approaches such as mindfulness and cognitive behavioral therapy (CBT).
  • Complementary health: Stress-relieving and relaxation techniques can help a person feel better. Examples include meditation, yoga, tai chi, and acupuncture. Hypnotherapy may help reduce symptoms of stomach upset, bloating, and stomach pain in those with IBS, according to an article in the journal Clinical and Translational Gastroenterology.

According to the ADAA, a person can reduce anxiety and stress by taking short breaks to breathe deeply for 1 minute at a time throughout the day. A person should breathe slowly through the nose and let the stomach inflate. As they exhale, they should let their stomach deflate.

Over time, a person may see a reduction in their symptoms.

Doctors may also prescribe medications to treat diarrhea. Examples of these medications include:

  • Antidiarrheals: Medications such as loperamide (Imodium) may help reduce the incidence of diarrhea.
  • Antispasmodics: These medications reduce the frequency of contractions in the muscles in the intestines. As a result, the stool does not move through the intestines as quickly. Doctors may prescribe medications such as hyoscyamine (Levsin) and dicyclomine (Bentyl) to help.
  • Bile acid sequestrants: These medications can bind to extra bile in the intestine that may otherwise lead to diarrhea. An example is cholestyramine (Questran).
  • Alosetron hydrochloride: The Food and Drug Administration (FDA) have approved a medicine called alosetron hydrochloride (Lotronex) to treat IBS in females whose primary symptom is diarrhea. Females are more likely to experience IBS symptoms than males, according to the ADAA.

Over-the-counter supplements, such as fiber or probiotics, may also help. A person should always speak to their doctor before they start taking these medications. The doctor can ensure that the product does not interfere with any other medicines that the person may be taking or affect any underlying health conditions.

A person should see their doctor if they have diarrhea for 2–4 weeks without an underlying illness (such as a bacterial or viral infection) causing it.

Other symptoms that indicate that a person may need to see a doctor include:

  • blood in the stool
  • fatigue
  • unexplained weight loss

A doctor can perform testing to determine the underlying cause of chronic diarrhea.

In addition to IBS-D, inflammatory bowel disease and celiac disease are possible underlying causes.

Anxiety can lead to unnecessary worry and stress that manifests itself in a number of ways, including stomach upset that causes diarrhea.

If a person’s diarrhea turns into a frequent, chronic occurrence, they should seek medical treatment.

There are medications and at-home methods to manage anxiety and reduce the physical stomach symptoms that can accompany it.