Psychotic symptoms are associated with elevated tau PET signal in the amygdala independent of Alzheimer's disease clinical severity and amyloid burden

BackgroundPsychosis in Alzheimers disease (AD) is associated with worse outcomes, yet no established biomarkers exist for early diagnosis and intervention. We compared tau PET burden across older individuals with and without psychotic symptoms. Methods[18F]AV1451 tau PET binding was compared between 26 Alzheimers Disease Neuroimaging Initiative (ADNI) subjects with psychotic symptoms (delusions and/or hallucinations) and 26 ADNI subjects without psychotic symptoms, matched for age, sex, race/ethnicity, and clinical severity. Tau was assessed on a region-of-interest and voxel level, corrected for amyloid PET burden. ResultsTau was greater in individuals with psychotic symptoms in the amygdala in region-of-interest analyses, and in amygdala, thalamus, putamen, right hippocampus, right entorhinal cortex, and right frontal cortex in voxel-based analyses. When considering different onset and type of psychotic symptoms, tau binding was greatest in those with concurrent delusions. ConclusionElevated tau in limbic regions may be relevant for psychotic symptoms in aging and AD.