INTRODUCTION: Late-life onset psychosis is associated with faster progression to dementia in cognitively normal people, but little is known about its relationship to cognitive impairment in advance of dementia.
METHODS: Clinical and genetic data from 2,750 people over 50 without dementia were analyzed. Incident cognitive impairment was operationalized using the IQCODE and psychosis (MBI-psychosis) was rated using the Mild Behavioral Impairment Checklist. The whole sample was analyzed before stratification on APOE-ε4 status.
RESULTS: In Cox proportional hazards models, MBI-psychosis had a higher hazard rate (HR) for cognitive impairment relative to the No Psychosis group (HR:3.6, 95% CI:2.2-6, p<0.0001). The HR for MBI-psychosis was higher in APOE-ε4 carriers and there was an interaction between the two (HR for interaction: 3.4, 95% CI:1.2-9.8, p=0.02).
DISCUSSION: Psychosis assessment in the MBI framework is associated with incident cognitive impairment in advance of dementia, these symptoms may be particularly important in the context of APOE genotype.