Genetic and Hormonal Contributions to Psychosis Symptoms in Alzheimer's Disease: A Sex-Stratified Analysis.

OBJECTIVE

Psychosis in Alzheimer's disease (AD), including hallucinations and delusions, affects up to 50% of patients and is linked to faster cognitive decline. Delusions can occur across AD, with persecutory delusions early and misidentification delusions late, while hallucinations emerge in advanced stages and predict greater cognitive and functional decline. The APOE4 allele is the strongest genetic risk factor for late-onset AD, although its influence on neuropsychiatric symptoms, including psychosis, remains unclear. This study examined the interaction between APOE4 status, sex, EHT use, and psychosis symptoms in AD using data from participants in the National Alzheimer's Coordinating Center Uniform Data Set.

METHODS

Generalized Additive Models assessed nonlinear associations between predictors and psychosis outcomes, including the presence of delusions, hallucinations, and their visual and auditory subtypes. Analyses were stratified by sex (males: n = 13,841, females: n = 15,354). Predictor variables included APOE4 status, current use of estrogen hormone therapy (EHT) in females. Due to limited data availability, CSF biomarkers (Aβ1-42, p-tau181, t-tau) could not be included in the main models and were instead examined in a secondary sub analysis.

RESULTS

APOE4 homozygosity was associated with significantly greater odds of delusions in the past month in both males and females, with a stronger effect in females (p<0.05). In females only, APOE4 homozygosity was significantly associated with hallucinations, with no effect in males (p<0.05). EHT was associated with lower risk of hallucinations in females (p<0.05).

CONCLUSIONS

These findings underscore sex-specific genetic and biological contributors to psychosis in AD and support sex-stratified approaches to understanding and addressing psychosis symptoms in clinical settings.