Objective: The authors explored classes of neuropsychiatric symptoms (NPSs) in Alzheimer’s disease (AD), examined the relationship between NPS classes on rate of functional decline over time, and determined whether effects of individual symptoms on functional decline remained after controlling for NPS classes. Methods: The authors longitudinally analyzed 9,797 study participants with mild cognitive impairment or AD at baseline in the National Alzheimer’s Coordinating Center Uniform Data Set. Function was measured with the Functional Assessment Questionnaire, and NPSs were assessed by using clinician judgment. Latent class analysis (LCA) was used to identify clusters of individuals who shared similar NPS profiles. Linear mixed models were used to estimate the relationship between NPS classes and individual symptom profiles in functional decline over time. Results: LCA revealed four distinct NPS classes: an asymptomatic-mild group (48.2% of the sample, N=4,721), a second group predominan