Common acne drug may protect against schizophrenia

Scientists found that adolescents receiving mental health care who were prescribed the antibiotic doxycycline were significantly less likely to develop schizophrenia later in life than those treated with other antibiotics.

Experts believe the results suggest a potential new use for an existing and widely available medication as a preventive treatment for severe mental illness.

Understanding Schizophrenia and Its Early Onset

Schizophrenia is a serious mental health disorder that typically begins in early adulthood and is often marked by hallucinations, delusions, and disorganized thinking. Finding ways to reduce the risk of developing the condition has long been a major challenge for mental health researchers.

To explore possible prevention strategies, scientists from the University of Edinburgh, working with colleagues from the University of Oulu and University College Dublin, analyzed extensive healthcare data from Finland using advanced statistical models.

The study examined health records from more than 56,000 adolescents who had received antibiotics while attending mental health services. Those treated with doxycycline showed a 30-35 percent lower risk of later developing schizophrenia compared with peers who received other types of antibiotics.

The research team believes this protective effect could be related to doxycycline's impact on inflammation and brain development.

How Doxycycline Might Protect the Brain

Doxycycline is a broad-spectrum antibiotic commonly prescribed for infections and acne. Earlier studies have found that it can reduce inflammation in brain cells and affect synaptic pruning -- a normal developmental process in which the brain trims and strengthens neural connections. Too much pruning has been linked to the onset of schizophrenia.

Further analysis confirmed that the reduced risk was not merely due to participants being treated for acne instead of infections and was unlikely to result from other unnoticed differences between the groups.

Professor Ian Kelleher, study lead and Professor of Child and Adolescent Psychiatry at the University of Edinburgh, explained: "As many as half of the people who develop schizophrenia had previously attended child and adolescent mental health services for other mental health problems. At present, though, we don't have any interventions that are known to reduce the risk of going on to develop schizophrenia in these young people. That makes these findings exciting."

He added: "Because the study was observational in nature and not a randomized controlled trial, it means we can't draw firm conclusions on causality, but this is an important signal to further investigate the protective effect of doxycycline and other anti-inflammatory treatments in adolescent psychiatry patients as a way to potentially reduce the risk of developing severe mental illness in adulthood."

The study was published in the American Journal of Psychiatry and involved researchers from the University of Edinburgh, University of Oulu, University College Dublin, and St John of God Hospitaller Services Group. Funding was provided by the Health Research Board.