How Antibiotics Affect The Brain New Evidence On Anxiety

Overuse of antibiotics can have a negative impact not only on your gut health, but also on your mental health. This conclusion was reached by researchers from the First Hospital of Chongqing Medical University (China) after studying the effect of antibacterial therapy on anxiety in mice and humans. The results of the work were published in the journal Molecular Psychiatryreports Medical Xpress.

Antibiotics are widely used to treat bacterial infections, but they disrupt the balance of the intestinal microbiota, a community of microorganisms involved in digestion and regulation of immune processes. Microbiota is linked to brain function through the gut-brain axis and may influence inflammation and cognitive function.

Effect in mice

During the experiments, scientists administered antibiotics to adult mice and observed changes in their behavior.

Animals receiving the drugs showed pronounced signs of anxiety. The analysis showed significant changes in the composition of the intestinal microbiota, a decrease in the level of short-chain fatty acids and disruption of lipid metabolism between the intestine and the brain. At the same time, these mice had significantly reduced levels of acetylcholine, a neurotransmitter that plays an important role in the functioning of the nervous system, in the intestines, blood and hippocampus. This decrease was directly correlated with anxious behavior.

Results in humans

The researchers then analyzed the people’s data. The study included three groups: patients who had recently taken antibiotics, patients without antibiotic therapy, and healthy volunteers.

People who received antibiotics also had pronounced symptoms of anxiety, changes in the composition of the microbiota (primarily a decrease in bacteria of the genusBacteroides), decreased levels of short-chain fatty acids and decreased levels of acetylcholine in feces and serum.

Additional experiments showed that administration of methacholine, a derivative of acetylcholine, reduced anxiety-like behavior in mice and reduced microglial activation in the hippocampus. This indicatesa possible mechanism for the relationship between microbiota, neurotransmitter balance and emotional state.

The authors note that the effects of antibiotics on mood appear to be reversible, but are aggressive andinappropriate use of such drugs may pose a risk to mental health. In the future, the results of the study may form the basis of new approaches to restoring the microbiota and reducing anxiety disorders after antibacterial therapy.