Aubrey S. Johnson, et al. – Columbia University.
Background: Many patients with AD experience psychotic symptoms, but the factors determining which patients experience these symptoms are unclear.
This Study: Johnson and colleagues compared tau positron emission tomography (PET) data from 26 participants in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) with psychotic symptoms with data from 26 ADNI participants without psychotic symptoms.
- Non-psychotic controls were matched for clinical status, removing a confounding factor from prior studies. The two groups did not significantly differ in amyloid burden as measured by PET.
- Patients with psychotic symptoms had significantly higher accumulation of tau in the amygdala.
- Tau levels in regions associated with Braak staging were similar across the two groups, affirming that increased tau in the amygdala was not an artifact of more advanced disease in the psychosis group.
Bottom Line: Tau accumulation in the amygdala may be a biomarker for psychosis in AD.
Open Question: The data collected in this study were cross-sectional. Does increased tau in the amygdala precede psychosis onset (i.e. could it serve as a predictive measure)?
