Gut Instinct: Post-Traumatic Stress Disorder May Be Related to Gut Bacteria, Scientific Study Says

How humans react to fearful and stressful situations may depend on the quality of bacteria in the gut, known as "gut microbiota," according to a scientific study published in Nature October 23. This research may eventually lead to practical applications that could help treat post-traumatic stress disorder (PTSD).

Scientists trained mice to associate a specific tone with an electric shock, like how humans check their phones when they hear the tone alerting them to a new text. Those associations developed normally within two groups of mice: control animals that were simply part of the experiment and those that were fed antibiotics, which depleted the bacteria in their guts.

Researchers then began playing the tone without administering the electric shock.

Mice who were lacking in gut microbiota took longer to stop being afraid after hearing the tone, as did mice raised in sterile environments who did not develop a gut microbiota. Control animals adapted to the change faster.

"In mammals, changes in the composition of the microbiota can influence many physiologic processes (including development, metabolism and immune cell function) and are associated with susceptibility to multiple diseases," states the abstract synopsis of the study. "Alterations in the microbiota can also modulate host behaviors—such as social activity, stress, and anxiety-related responses—that are linked to diverse neuropsychiatric disorders."

post-traumatic stress disorder, PTSD
Post-traumatic stress disorder may be linked to bacteria in the gut, according to a recent study. Getty

Researchers found that mice who had a difficult time overcoming their learned response to the tone were had low levels of four gut bacteria metabolites in the fluid that surrounds the brain. According to Cosmos Magazine, two of those metabolites have been linked to both autism and schizophrenia in humans.

Communication between the gut and the brain is accomplished through the gut-brain axis, a connection between the emotional and cognitive centers of the brain and intestinal functions. This link also allows the endocrine, immune and autonomic nervous system to "talk" to each other, according to PsychScene Hub.

No conclusive evidence has been found yet, but research indicates that the gut microbiota is connected to neuropsychiatric disorders. Gut bacteria may help regulate things like the body's use of brain chemicals, such as dopamine. Further research into how the gut and brain work together could lead to new treatment options for patients with those disorders.

Poor gut health can manifest in conditions like diarrhea and heartburn. Look for unintentional changes to your weight, which could be a sign of an impaired ability to absorb nutrients. According to Healthline, other symptoms can include constant fatigue, skin irritation and an upset stomach.

Johns Hopkins Medicine says that keeping the gut healthy is an important part of overall health. One suggested way to maintain intestinal health is by eating enough fiber, sticking with a diet including plenty of fruits and vegetables.

Foods that are rich in probiotics, such as yogurt and kefir, are also recommended along with pickled or fermented foods.