Overview
- Researchers analyzed Finnish nationwide health registers for more than 56,000 people who used adolescent psychiatric services and received antibiotics, comparing doxycycline users with peers given other antibiotics.
- Doxycycline exposure was associated with a roughly 30–35% lower 10-year risk of schizophrenia relative to other antibiotics in this high-risk group.
- Absolute risks were about 2.1% for non-doxycycline antibiotic users versus 1.4–1.5% for those prescribed doxycycline, estimated with an emulated target-trial approach.
- The signal appeared specific to schizophrenia and did not extend to broader non-affective psychoses in the study’s analyses.
- Authors emphasize the observational design, prescription-record limitations and potential residual confounding, and they call for randomized clinical trials and mechanistic studies.