Cyprus Times

Antibiotic Overuse Linked to Increased Anxiety Levels

Published January 21, 2026, 08:09
Antibiotic Overuse Linked to Increased Anxiety Levels

A new study published in Molecular Psychiatry suggests a link between excessive antibiotic use and increased anxiety levels. Researchers found that antibiotics can alter the gut microbiome, negatively impacting mental health through the gut-brain axis. Specifically, the study showed changes in gut bacteria (Firmicutes and Bacteroidota), reduced short-chain fatty acids (SCFAs), disrupted lipid metabolism, and lower levels of acetylcholine in both mice and humans who had taken antibiotics. The research involved experiments on mice, where antibiotic administration induced anxiety-like behaviors, as well as analysis of stool and blood samples from three groups of people: those who had recently taken antibiotics, those who had not, and a control group. The results showed similar patterns of changes in the microbiome and acetylcholine levels in both cases. Notably, the study identified a potential way to reverse some of these effects. Exogenous administration of methacholine, a derivative of acetylcholine, effectively relieved anxiety symptoms and suppressed the activation of hippocampal microglia cells in mice treated with antibiotics. In conclusion, the study highlights the potential impact of antibiotic overuse on mental health and offers a possible therapeutic approach through acetylcholine replenishment. Understanding the connection between the gut microbiome and mental health is crucial for developing new strategies for the prevention and treatment of mental disorders.