Hallucinations and delusions are associated with elevated tau PET signal independent of age, clinical severity, and amyloid burden.

INTRODUCTION

Psychosis in Alzheimer's disease (AD) is associated with worse outcomes, yet no established biomarkers exist for early diagnosis and intervention. We compared tau positron emission tomography (PET) burden across older individuals with and without psychotic symptoms.

METHODS

[18F]AV1451 tau PET binding was compared between 32 Alzheimer's Disease Neuroimaging Initiative (ADNI) subjects with psychotic symptoms (delusions and/or hallucinations) and 32 ADNI subjects without psychotic symptoms, matched for age, sex, race/ethnicity, and clinical severity. Tau was assessed in a priori regions of interest (ROIs) and in voxelwise analyses, both corrected for amyloid PET burden.

RESULTS

Tau was greater in individuals with psychotic symptoms in the amygdala, hippocampus, frontal cortex, and early, middle, and late Braak stage regions in primary analyses. When considering subgroups, tau binding was greatest in those with concurrent delusions.

DISCUSSION: Greater than expected tau burden for age, clinical severity, and amyloid burden may be relevant for psychotic symptoms in older adults.

HIGHLIGHTS: Tau positron emission tomography (PET) was elevated in individuals with psychosisElevated tau was independent of Alzheimer's disease (AD) clinical severity and amyloid burdenThere was variability in the regional distribution depending on psychosis type.