Ever "gone with your gut" when making a decision? You’re probably receiving signals from your gastrointestinal tract, which communicates directly with your brain…
It’s widely recognised that emotions can directly affect stomach function. As early as 1915, influential physiologist Walter Cannon noted that stomach functions are changed in animals when frightened. The same is true for humans. Those who stress a lot often report diarrhea or stomach pain.
We now know this is because the brain communicates with the gastrointestinal system. A whole ecosystem comprising 100 trillion bacteria living in our bowels is an active participant in this brain-gut chat.
Recent discoveries around this relationship have made us consider using talk therapy and antidepressants as possible treatments for symptoms of chronic gut problems. The aim is to interfere with the conversation between the two organs by telling the brain to repair the faulty bowel.
Our research found talk therapy can improve depression and the quality of life of patients with gastrointestinal conditions. Antidepressants may also have a beneficial effect on both the course of a bowel disease and accompanying anxiety and depression.
What are gastrointestinal conditions?
Gastrointestinal conditions are incredibly common. About 20% of adults and adolescents suffer from irritable bowel syndrome (IBS), a disorder where abdominal discomfort or pain go hand-in-hand with changes in bowel habits. These could involve chronic diarrhea and constipation, or a mixture of the two.
IBS is a so-called functional disorder, because while its symptoms are debilitating, there are no visible pathological changes in the bowel. So it is diagnosed based on symptoms rather than specific diagnostic tests or procedures. People with chronic gut conditions can experience severe pain that affects their quality of life
Subtypes of inflammatory bowel disease are Crohn’s disease and ulcerative colitis. Around five million people worldwide, and more than 75,000 in Australia, live with these conditions. This is contrary to inflammatory bowel disease (IBD), a condition where the immune system reacts in an exaggerated manner to normal gut bacteria. Inflammatory bowel disease is associated with bleeding, diarrhea, weight loss and anemia (iron deficiency) and can be a cause of death. It’s called an organic bowel disease because we can see clear pathological changes caused by inflammation to the bowel lining.
People with bowel conditions may need to use the toilet 20 to 30 times a day. They also suffer pain that can affect their family and social lives, education, careers and ability to travel. Many experience anxiety and depression in response to the way the illness changes their life. But studies also suggest those with anxiety and depression are more likely to develop bowel disorders. This is important evidence of brain-gut interactions.
How the brain speaks with the gut
The brain and gut speak to each other constantly through a network of neural, hormonal and immunological messages. But this healthy communication can be disturbed when we stress or develop chronic inflammation in our guts.
Stress can influence the type of bacteria inhabiting the gut, making our bowel flora less diverse and possibly more attractive to harmful bacteria. It can also increase inflammation in the bowel, and vulnerability to infection.
Chronic intestinal inflammation may lower our sensitivity to positive emotions. When we become sick with conditions like inflammatory bowel disease, our brains become rewired through a process called neuroplasticity, which changes the connections between the nerve signals.
Anxiety and depression are common in people suffering chronic bowel problems. Approximately 20% of those living with inflammatory bowel disease report feeling anxious or blue for extended periods of time. When their disease flares, this rate may exceed 60%.
Interestingly, in a recent large study where we observed 2,007 people living with inflammatory bowel disease over nine years, we found a strong association between symptoms of depression or anxiety and disease activity over time. So, anxiety and depression are likely to make the symptoms of inflammatory bowel disease worse long-term.
It makes sense then to offer psychological treatment to those with chronic gut problems. But would such a treatment also benefit their gut health? Soon to be discovered.