A LARGE Finnish study has found that doxycycline use among adolescents receiving psychiatric care was linked to a 30–35% lower risk of developing schizophrenia later in life.
Exploring Doxycycline’s Neuroprotective Potential
Doxycycline, widely prescribed for bacterial infections, has long been known for its anti-inflammatory properties. Researchers have theorised that these effects might extend to the brain, protecting against excessive neural pruning and inflammatory processes thought to contribute to psychosis. Since up to half of those who develop schizophrenia have previously received adolescent mental health support, identifying an accessible preventive intervention could transform early psychiatric care.
Nationwide Study Reveals Significant Risk Reduction
The study, titled Doxycycline Use in Adolescent Psychiatric Patients and Risk of Schizophrenia, used Finnish health register data covering 56,395 adolescents aged 13 to 18 who had taken antibiotics. Of these, 16,189 (28.7%) had used doxycycline. After 10 years of follow-up, the analysis revealed that the risk of schizophrenia was 2.1% among those taking other antibiotics, compared with just 1.4–1.5% among doxycycline users, depending on dose. This corresponds to a relative risk reduction of around 30–35%. The strongest effects were observed in those receiving cumulative doses above 1,500 mg. These results suggest that doxycycline’s neuroprotective actions could help mitigate long-term psychiatric vulnerability, though further trials are needed to confirm causality.
Implications for Prevention and Future Research
While these findings are preliminary, they highlight the potential for doxycycline to be repurposed as a preventive tool for at-risk adolescents. If validated through controlled clinical trials, this approach could provide an inexpensive, safe intervention to reduce schizophrenia risk. For clinicians, it reinforces the growing importance of inflammation-focused strategies in mental health prevention and care.
Reference
Lång U et al. Doxycycline use in adolescent psychiatric patients and risk of schizophrenia: an emulated target trial. American Journal of Psychiatry. 2025;DOI:10.1176/appi.ajp.20240958.
