Gut Feeling No More: Link Between PTSD & Microbes Found

If you were apprehensive about the growing scientific buzz around the gut and brain then these new studies might put you at ease. A series of studies carried out at Stellenbosch University in South Africa have shown that people who suffer from psychiatric disorders have shown to have a lower level of immune fighting bacteria and higher levels of inflammation in their bodies.
When scientists looked at the composition of the gut microbiome of PTSD patients, they found they had very low levels of a combination of three bacteria: actinobacteria, lentisphaerae, and verrucomicrobia. Previous studies have shown that these bacteria play an important role in regulating inflammation and the immune system. In turn, high levels of inflammation and changes in immune functioning can influence the brain, its functioning and behaviour.

These findings bring scientists one step closer to understanding how the gut microbiome plays a role in the disorders such as PTSD.

In the last 10 to 15 years scientists have discovered a vast number of functions performed by the trillions of bacteria living inside the human gut (called the gut microbiome). These include the metabolism of food and medicine and protection against infections. However the gut microbiome also plays an important role in brain functioning and behaviour.

“There is a complex interaction between the brain, the gut and gut microbiome called the gut-microbiome-brain axis. The microbiome can influence brain functioning and behaviour through several mechanisms. It communicates with the enteric nervous system – a complex system of millions of nerves in the lining of the gut. It also produces hormones, immune molecules and toxins which affect the brain.” said lead scientist in the research .

It is unclear when these changes in the microbiome might have taken place in PTSD sufferers. They may have occurred early in life as a response to childhood trauma, as people who suffer high levels of childhood trauma have a higher risk of developing anxiety and stress-related disorders later.

This correlates with another finding in the study, where people who experienced high levels of trauma during childhood had significantly lower levels of two of the earlier mentioned bacteria (Actinobacteria and Verrucomicrobia) compared to people with no or minimal childhood trauma.

Understanding how the bacteria in the gut affects the brain and behaviour is the first step in establishing how different factors influence susceptibility and resilience to PTSD.

It is now believed that the low levels of this trio of bacteria in PTSD patients may have contributed to a deficient immune system and heightened inflammation, which may have contributed to symptoms of PTSD. More research is to continue into the area.

This article was originally published in The Conversation.