Common antibiotic Linked to Lower Schizophrenia Risk in New Study
November 5, 2025 – 9:00 A.M. – A widely-used antibiotic, doxycycline, might potentially be associated with a reduced risk of developing schizophrenia in young people, according to research published today in the American Journal of Psychiatry. The observational study suggests adolescents treated with doxycycline experienced a 30 to 35 percent lower likelihood of being diagnosed with schizophrenia in adulthood compared to those receiving other antibiotics.
The study, conducted by researchers in Finland, analyzed data from over 56,000 adolescents, with more than 16,000 receiving doxycycline, commonly prescribed for infections and acne. While the research doesn’t prove a causal link – it was not a randomized controlled trial – the findings are prompting calls for further investigation.
Researchers hypothesize the antibiotic’s potential benefit may stem from its ability to reduce inflammation in the brain and influence synaptic pruning, the process where the brain eliminates unnecessary neuron connections. Disruptions in this pruning process have been implicated in the development of schizophrenia, a debilitating mental illness affecting approximately 23 million people worldwide.
“The results are preliminary but exciting,” the research team noted.
Lead author Ian Kelleher, professor of child and adolescent psychiatry at the University of Edinburgh, emphasized the importance of the findings. “This is an important signal to further investigate the possible protective effect of doxycycline and other anti-inflammatory treatments in adolescents in psychiatry,” he said, adding that this approach “could potentially reduce the risk of developing a serious mental illness in adulthood.”
However, experts caution against drawing definitive conclusions. Dominic oliver, a psychiatry researcher at the University of Oxford, warned, “Many other treatments initially seemed promising but proved ineffective in large studies.”
Dr.Katharina Schmack from the Francis Crick Institute in the United Kingdom, while acknowledging the statistically notable results, pointed out the modest absolute risk reduction. “Rather of about five out of 100 people, roughly two to three out of 100 people would now develop schizophrenia” fifteen years after doxycycline treatment, she explained.
Schmack further stated, “Uncovering clinical connections in studies like this is critically important as it can trigger further biological investigations.” Both Oliver and Schmack were not involved in the study.
The research highlights the need for continued exploration into the complex interplay of brain development,inflammation,and the risk factors associated with schizophrenia,a condition that typically emerges in early adulthood and currently has no cure,though symptoms can be managed with medication.
