Constipation is a common symptom of depression that many people don’t recognise as such.
Gut problems affect around one-in-three people experiencing depression, research finds.
Some report that bowel problems have the biggest impact in lowering their quality of life.
Now, new research has linked both gut problems and the experience of depression to low levels of the neurotransmitter, serotonin.
Increasing levels of serotonin may help both conditions, suggesting an effective treatment.
Dr Kara Gross Margolis, the study’s first author, said:
“The gut is often called the body’s ‘second brain’.
It contains more neurons than the spinal cord and uses many of the same neurotransmitters as the brain.
So it shouldn’t be surprising that the two conditions could be caused by the same process.”
The conclusions come from a study of mice with a genetic mutation that impairs their ability to make serotonin.
Dr Margolis explained the effect:
“Basically, the mice were constipated and they showed the same kind of GI changes we see in people with constipation.”
However, a drug designed to increase serotonin levels was able to treat constipation in the mice.
Even better, the results showed that neurogenesis (growth of new neurons) is possible in the gut.
Dr Margolis said:
“Though it’s been known for many years that neurogenesis occurs in certain parts of the brain, the idea that it occurs in the gut nervous system is relatively new.”
Neurogenesis may help to treat both depression and constipation in humans using the 5-HTP slow-release therapy trialled on mice.
Dr Margolis said:
“We see a reduction of neurons in the GI tract with age, and that loss is thought to be a cause of constipation in the elderly.
The idea that we may be able to use slow-release 5-HTP to treat conditions that require the development of new neurons in the gut may open a whole new avenue of treatment.”
Although 5-HTP is currently available as a supplement, it is fast-release, which is not scientifically proven to work.
The researchers plan to test their slow-release 5-HTP on people with treatment-resistant depression.
About the author
Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology.
He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book “Making Habits, Breaking Habits” (Da Capo, 2003) and several ebooks:
- Accept Yourself: How to feel a profound sense of warmth and self-compassion
- The Anxiety Plan: 42 Strategies For Worry, Phobias, OCD and Panic
- Spark: 17 Steps That Will Boost Your Motivation For Anything
- Activate: How To Find Joy Again By Changing What You Do
The study was published in the journal Gastroenterology (Israelyan et al., 2019).