Researchers from the University of Edinburgh have found that the common antibiotic doxycycline may lower the likelihood of developing schizophrenia in certain young people. The findings were published in the American Journal of Psychiatry (AJP).

Doxycycline is a broad-spectrum antibiotic often used to treat infections and acne. Previous studies have shown that it reduces inflammation in brain cells and may affect so-called synaptic pruning — a process in which the brain eliminates excess neural connections. According to neuroscientists, excessive synaptic pruning is associated with the development of schizophrenia.

Schizophrenia typically emerges in early adulthood and is a severe disorder characterized by hallucinations, delusions, and disorganized thinking.

The researchers analyzed data from over 56,000 adolescents who had received psychiatric care and various antibiotics. Among those who took doxycycline, the risk of developing schizophrenia was 30–35% lower than among their peers treated with other antibiotics.

Scientists emphasized that the reduced risk could not be explained by acne treatment: the protective effect persisted even after accounting for other factors such as diagnosis and overall health condition.

“Almost half of the participants who later developed schizophrenia had previously sought help from child psychiatric services for other issues,” noted study lead Professor Ian Kelleher.

According to the researchers, these findings open new possibilities for studying anti-inflammatory drugs. In particular, they plan to explore whether doxycycline could help prevent other severe psychiatric disorders in adolescents.