Treating the Gut in Mood Disorders: The Link between Anxiety, Depression and IBS

Dr. Leah Hassall, ND

We have all experienced that feeling of a “pit” or “butterflies” in the stomach when we are scared, anxious or excited. Is this just imagined or are the brain and the stomach actually communicating? The idea of a connection between the brain and the gut where emotions and mood can trigger physiological changes in the digestive tract has actually been known for quite some time in medicine. This connection between our nervous system and our gastrointestinal system is known as the “brain-gut connection” and refers to system of nerves and chemical messengers communicating information from the brain’s emotional networks to the stomach, small intestine, colon and associated organs and vice versa. Because of this connection, scientists are now asking the question: Could chronic digestive issues like irritable bowel syndrome (IBS) be related to your mood? The research is showing that in fact, there may be a connection. Studies show that people with IBS (irritable bowel syndrome) are about 3.5 times more likely to develop psychiatric disorders such as anxiety, depression, bipolar and sleep disorders. These studies have also shown that of these disorders, anxiety is the most common in people with IBS.

IBS can be thought of a complex interaction between many factors including overgrowth of “good bacteria” in the small intestine (also known as SIBO), abnormal intestinal motility and dysregulation of the nervous system. There is no research to say that mood disorders like anxiety or depression cause IBS, but they have been shown to make symptoms worse and treatment of these conditions can help reduce IBS severity. There is also some evidence supporting the opposite: that treating or managing IBS can result in improvements in anxiety and depression.

IBS and Serotonin

Serotonin is a chemical messenger in the body (known as a neurotransmitter) that has multiple roles in the body related to mood and digestion. We now know that there are serotonin receptors in the wall of the intestines and serotonin is thought to regulate digestive function. This has made researchers dub the gut as the body’s “second brain”. Evidence now strongly suggests that serotonin is involved in regulating intestinal motility and section of digestive enzymes and that alterations in the function of this system may be responsible for IBS symptoms.

Treating IBS and Mood Disorders

Treating IBS-associated mood disorders involves treating both the mind and the digestive tract. Tools that I love to use to treat mood disorders include herbal medicine, specific neurotransmitter therapy like GABA, glycine, 5HTP and theanine, acupuncture, counselling, exercise therapy and dietary changes. The number one cause of IBS is an overgrowth of bacteria in the small intestine (SIBO). Normally, the small intestine is relatively sterile from bacteria. When they overgrow due to stress, infection (like travellers’ diarrhea and the flu) and certain drug therapies (i.e. acid blockers), they produce excess gas, bloating, pain and stool changes (diarrhea, constipation or a mix of both). At Sage Clinic, we use breath testing to determine if people have an overgrowth of bacteria in the small intestine and then use herbs and/or targeted antibiotic therapy to correct the overgrowth. Once the overgrowth has been corrected, we use gut-healing protocols and specific probiotic therapy to restore normal gut function.

To learn more about small intestinal bacterial overgrowth (SIBO) and the breath testing we use, please visit us at:


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