Maties psychiatrists link PTSD to a gut feeling

Low levels of intestinal bacteria are linked to post-traumatic stress disorder, according to researchers at Stellenbosch University.

They found lower levels of three bacteria in the gastrointestinal tract of people with PTSD than in people who had experienced significant trauma but stopped short of developing PTSD.

People who experienced childhood trauma had lower levels of two of the bacteria‚ said lead researcher Stefanie Malan-Muller‚ a postdoctoral fellow in the psychiatry department at the Stellenbosch medical school.

“What makes this finding interesting is that individuals who experience childhood trauma are at higher risk of developing PTSD later in life‚ and these changes in the gut microbiome possibly occurred early in life in response to childhood trauma‚” said Malan-Muller‚ who worked with researchers from the University of Colorado Boulder‚ in the US.

PTSD can develop after a person experiences a life-threatening trauma‚ and gut bacteria is the latest addition to a list of factors that influence whether it will do so‚ including living conditions‚ childhood experiences and genetic makeup.

Scientists have discovered that the enteric nervous system — the network of neurons that controls the digestive tract — acts as a “second brain”‚ with a particular influence on mood.

People with healthy and diverse gut microbiomes are less likely to be depressed or anxious‚ and research on mice has shown that those with no gut bacteria display “autistic” social traits. When they eat probiotics‚ their symptoms vanish.

Malan-Muller said stress and emotions change the composition of the gut microbiome and weaken the intestinal lining‚ leading to bacteria and toxins entering the bloodstream and causing inflammation‚ which is implicated in several psychiatric disorders.

“Levels of inflammatory markers measured in individuals shortly after a traumatic event were shown to predict later development of PTSD‚” she said in the journal Psychosomatic Medicine.

“We therefore hypothesise that the low levels of those three bacteria may have resulted in immune dysregulation and heightened levels of inflammation in individuals with PTSD‚ which may have contributed to their disease symptoms.”

Malan-Muller’s research group is now launching a large-scale study to unravel the connections between the gut microbiome and the brain‚ in collaboration with the South African Microbiome Initiative in Neuroscience.

It will focus on people that have been diagnosed with any kind of psychiatric disorder in comparison to healthy control groups.