Introduction Neuropsychiatric symptoms are common in Alzheimer's disease. Previous
research has attempted to identify subsyndromes—sets of symptoms related to one another—
to clarify underlying mechanisms and treatment targets. We examined the stability of these
subsyndromes over time. Methods We administered the Neuropsychiatric Inventory annually
for 3 years to 447 patients with Alzheimer's disease recruited from memory clinics. We
conducted principal component analyses at each time point and multiple-group confirmatory …