A LARGE multicohort study has revealed that hospitalisation for infections is associated with higher risk of psychiatric and neurologic disorders over the following two years, with infectious encephalitis emerging as the strongest risk factor across most conditions.
Encephalitis Emerged as the Leading Risk FactorAmong 1,062,722 matched pairs (mean age 48.4 years; 51.5% female), infections were associated with a greater risk of most disorders.
The highest relative risk was for encephalitis, for example among cardiac infections (median ratio 6.54, 95% CI 3.78 to 11.31, p=2.0×10⁻¹¹), while the highest absolute risk difference was for cognitive deficits, also among cardiac infections (risk difference 12.37 percentage points; 19.08% [95% CI 18.51 to 19.65] versus 6.71% [95% CI 6.36 to 7.07]).
Implications for Brain Health and Pandemic PreparednessThese findings have identified infections, particularly those causing encephalitis, as important risk factors for psychiatric and neurologic disorders following hospitalisation, especially among adults.
Mapping 2-year psychiatric and neurologic risks after infections across body systems and age groups.
A LARGE multicohort study has revealed that hospitalisation for infections is associated with higher risk of psychiatric and neurologic disorders over the following two years, with infectious encephalitis emerging as the strongest risk factor across most conditions.
Multicohort Analysis Using the TriNetX Network
Researchers conducted a retrospective multicohort study using propensity score matching of patients hospitalised with an infection between 2014 and 2018, with two years of follow-up, using data from 62 healthcare organisations within the TriNetX US Collaborative Network. Cohorts hospitalised with an infection were compared with each other, with individuals hospitalised for noninfectious causes, and with the general population. The study mapped risks of 13 neurologic or psychiatric disorders, plus a composite category of cognitive deficits, across 10 body systems and four age groups, using restricted mean time lost, absolute risk difference, and infection specificity via network meta-analysis.
Encephalitis Emerged as the Leading Risk Factor
Among 1,062,722 matched pairs (mean age 48.4 years; 51.5% female), infections were associated with a greater risk of most disorders. The highest relative risk was for encephalitis, for example among cardiac infections (median ratio 6.54, 95% CI 3.78 to 11.31, p=2.0×10⁻¹¹), while the highest absolute risk difference was for cognitive deficits, also among cardiac infections (risk difference 12.37 percentage points; 19.08% [95% CI 18.51 to 19.65] versus 6.71% [95% CI 6.36 to 7.07]). Similar, stronger patterns emerged versus the general population.
Children also faced increased risks, though absolute risk differences were lower than in adults. Across 45 head-to-head comparisons, infectious encephalitides were the leading risk factor for 7 of 14 disorders and among the top three for 12 of 14.
Implications for Brain Health and Pandemic Preparedness
These findings have identified infections, particularly those causing encephalitis, as important risk factors for psychiatric and neurologic disorders following hospitalisation, especially among adults. As this was an observational study using matched cohorts, causality cannot be established. The authors have suggested that these results could help guide research into underlying mechanisms and inform future pandemic preparedness.
Reference
Taquet M et al. Mapping 2-year psychiatric and neurologic risks after infections across body systems and age groups. JAMA Psychiatry. 2026;DOI:10.1001/jamapsychiatry.2026.1904.
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