Association of antiseizure medication with lower amyloid and tau burden.

Network hyperexcitability is increasingly implicated in prodromal Alzheimer's disease and may be suppressed by antiseizure medications (ASMs). ASMs are widely prescribed to older adults, yet whether their use relates to Alzheimer's-disease biomarkers at the population level is unknown. In 52,537 participants in the National Alzheimer's Coordinating Center (NACC) study, we compared cerebrospinal-fluid biomarkers, amyloid and tau positron emission tomography (PET) between ASM users and non-users using inverse-probability-of-treatment weighting with gradient-boosted propensity scores. ASM users showed directionally lower amyloid across multiple brain regions, amplifying markedly in APOE ε4 carriers (Centiloid β = -25.7, p = 0.007). All three temporal tau-PET composites were significantly lower in users (META-temporal β = -0.05, p = 0.01). The amyloid finding replicated independently in the the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset (Centiloid β = -8.6, p = 0.01), whereas four comparator drug classes showed no amyloid signal. These convergent observational findings provide a quantitative framework for evaluating ASMs as candidate disease-modifying agents in Alzheimer's disease.