Individuals with accumulated community-acquired infections are at higher risk of mental illness over time, according to a
report in
Translational Psychiatry—and the risk rises with increasing numbers of infections for up to five years post-infection.
Why It’s Relevant
Infections are known to be associated with the onset and progression of mental disorders, potentially due to elevated inflammation. However, to date the association has been documented primarily in individuals with severe infections requiring hospitalization and not with community-acquired infections, which are much more common.
By the Numbers
- Using data from Clalit Health Service, the largest health organization in Israel, researchers compared 35,020 individuals (average age 26) with community-acquired infections—cytomegalovirus, herpes viruses, hepatitis, influenza, or toxoplasma gondii—and a matched sample of unexposed individuals.
- Exposed individuals were 1.18 times more likely to develop depression and 1.11 times more likely to develop anxiety than those not exposed. There was no significant effect for schizophrenia or bipolar disorders.
- Risk increased with the number of infections: 1.09 times increased risk for individuals with one infection, 1.19 for those with two, and 1.81 for those with three.
- These associations were stronger in females than males and in individuals over the age of 26 than those younger.
What’s More
The primary analysis followed participants through 2024, but a second analysis with a cut-off date of January 2020 produced similar results, suggesting that increased testing in the wake of COVID did not bias the findings.
The Other Side
The relatively young age of the cohort necessitates further studies with a longer follow-up time that also look at clinically relevant factors not measured in this study, including infection severity, treatments received, family psychiatric history, childhood trauma, parental education, and perinatal conditions.
Takeaway Message
The results underscore the importance of evaluating infection exposure and its association with individuals’ mental health, even in cases of relatively mild community-based infections. In especially vulnerable groups, early monitoring of infections may allow for preventive strategies, and future precision psychiatry initiatives should consider incorporating individuals’ immune profile into risk models.
Related Information
Source
Amit Kramer, et. al. Community-based infections and its association with mental disorder onset: a nationwide matched cohort study.
Translational Psychiatry. Published August 17, 2026.
doi:doi.org/10.1038/s41398-026-04384-w
(Image: Getty Images/iStock/Andrii Iemelyanenko)