Research Summary

Infections Linked to Higher 2-Year Neuropsychiatric Risk in US Cohort Study

Edited by:
Ashton L. Stahl

Key Highlights

  • The hospitalized-control analysis included 1,062,722 matched pairs.
  • Infectious encephalitides ranked as the leading infectious risk factor for 7 of 14 outcomes and among the top 3 for 12.
  • Absolute risk differences following infections were significantly smaller in children than in adults.

Hospitalization with infections across different body systems was associated with increased psychiatric and neurologic diagnoses over the subsequent 2 years, according to a retrospective multicohort study published in JAMA Psychiatry. Infectious encephalitides carried the greatest associated excess risk, while associations involving other infections varied by disorder.

Researchers examined electronic health records from 62 organizations in the TriNetX US Collaborative Network. They identified patients hospitalized between 2014 and 2018 and compared infection cohorts with one another, patients hospitalized for noninfectious causes, and general-population controls.

The study covered infections affecting 10 body systems and 4 age groups: ≤18, 19–44, 45–64, and ≥65 years. Propensity score matching accounted for 92 potential confounders. Investigators assessed 14 outcomes diagnosed from 1 month through 2 years after admission, excluding the first month to focus on post-acute diagnoses and limit reverse causation.

Study Findings

Comparisons with hospitalized controls included 1,062,722 matched pairs; mean age was 48.4 years, and 51.5% were female. Ratios of restricted mean time lost—a measure of time lived with a disorder during follow-up—exceeded 1 in 116 of 140 infection–disorder comparisons. For encephalitis following cardiac infections, the ratio was 6.54 (95% CI, 3.78–11.31). Cognitive deficits showed the largest absolute risk differences: after cardiac infections, risk was 19.08% versus 6.71% among hospitalized controls, a difference of 12.37 percentage points.

Across 45 head-to-head comparisons, infectious encephalitides ranked first for 7 of 14 outcomes and among the top 3 for 12 outcomes. Comparisons with the general population showed similar patterns, with higher restricted mean time lost ratios. Children also had higher risks, but the absolute risk differences were significantly smaller than in adults.

Clinical Implications

According to the authors, clinicians should consider a focused history of recent or past infections when assessing new-onset neurologic or psychiatric disorders, particularly atypical presentations such as late-onset psychosis or early cognitive decline. They stated that recognizing a possible postinfectious contribution may help patients and clinicians understand the disorder, even when management remains unchanged.

The authors identified potential recording errors, residual confounding, and reverse causation among the limitations. Findings were limited to hospitalized patients and may not generalize to milder infections.

Expert Commentary

“Results of this multicohort study show that hospital admission with an acute infection was associated with an increased risk of a broad range of psychiatric and neurologic disorders across ages and body systems in the following 2 years,” the researchers concluded.

Reference

Taquet M, Oliver P, Mezher A, et al. Mapping 2-year psychiatric and neurologic risks after infections across body systems and age groups. JAMA Psychiatry. 2026;83(9):957-966. doi:10.1001/jamapsychiatry.2026.1904