The presence of psychosis is associated with more rapid decline in Alzheimer's disease (AD), but the impact of paranoid (persecutory delusions) and misidentification (misperceptions and/or hallucinations) subtypes of psychosis on the speed of decline in AD is still unclear. Here we analysed data on Alzheimer's Disease Neuroimaging Initiative (ADNI)2 participants with late mild cognitive impairment or AD and we described individual trajectories of Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) scores using a semi-mechanistic, logistic model, with a mixed effects based approach, which accounted for drop-out, and adjusted for baseline Mini Mental State Examination scores. The covariate model included psychosis subtypes, age, gender, education, medications and Apo-e ε4 genotype. We found that ADAS-cog rate of increase was doubled in misidentification (βr,misid_subtype =0.63, p=0.031) and mixed (both subtypes) ((βr,mixed_subtype =0.70, p=0.003) compared to non-psychotic (or paranoid) subjects suggesting that the misidentification subtype may represent a distinct AD sub-phenotype associated with an accelerated pathological process. This article is protected by copyright. All rights reserved
