Infections, Antibiotics Associated With Subsequent Increased Risk for Mental Disorders in Youth

The risk for mental disorders increased after severe infections requiring hospitalizations in children.

A correlation was observed between infections requiring hospitalization and subsequent increased risk for mental disorders in children and adolescents, according to study data published in JAMA Psychiatry.

Investigators abstracted population data from nationwide Danish registers. The study cohort comprised all individuals born in Denmark between January 1, 1995 and June 30, 2012 (n=1,098,930). As exposure data, researchers captured infection history from birth until study conclusion, including severe infections requiring hospitalization and less severe infections treated in primary care. The primary outcome measures were diagnosis of any mental disorder in a hospital setting and any filled psychotropic medication prescription. Cox proportional hazard regression was performed to assess any correlations between infection history and subsequent mental health conditions.

Study participants (51.3% boys) were followed for 9,620,807.7 person-years up to mean (SD) age 9.76 (4.91). A total of 42,462 individuals were hospitalized for a mental disorder during study follow-up and 56,847 filled at least 1 prescription for psychotropic medication. Infections requiring hospitalization were associated with a subsequent increased risk for having a diagnosis of any mental disorder (hazard rate ratio [HRR], 1.84; 95% CI, 1.69-1.99) and increased risk for psychotropic medication use (HRR, 1.42; 95% CI, 1.37-1.46). Infection treated with anti-infective agents in the primary care sector was also associated with an increased risk for diagnosis of any mental disorder (HRR, 1.40; 95% CI, 1.29-1.51) and the use of psychotropic medication (HRR, 1.22; 95% CI, 1.18-1.26).  Antibiotic use was associated with significantly increased risk estimates compared with antivirals, antimycotics, and antiparasitic medications. The risk for mental disorders following infection had a dose-response association with infection severity and with temporal proximity to infection.

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Schizophrenia spectrum disorders, obsessive-compulsive disorder, personality and behavior disorders, autistic spectrum disorder, attention-deficit/hyperactivity disorder, oppositional defiant disorder and conduct disorder, and tic disorders were associated with the greatest risk following infections.

Although these data alone cannot prove causality, such information may provide a basis for further research on the association between infections, the immune system, and the etiology of mental disorders.


Köhler-Forsberg O, Petersen L, Gasse C, et al. A nationwide study in Denmark of the association between treated infections and the subsequent risk of treated mental disorders in children and adolescents [published online December 5, 2018]. JAMA Psychiatry. doi:10.1001/jamapsychiatry.2018.3428