Isolated hallucinosis in Alzheimer's disease is associated with African-American race

Abstract

Objectives: The aim of this investigation was to study the relationship between isolated hallucinosis and race in Alzheimer's disease.

Methods: This was a cross-sectional, case control study carried out at the Neuropsychiatry Service, outpatient clinic at the Johns Hopkins School of Medicine, USA. The participants were 237 community-residing patients with probable Alzheimer's disease according to NINCDS/ADRDA criteria were included in the study. 9 patients with isolated hallucinosis were compared to a control group of 228 patients who had neither delusions nor hallucinations. Patients with only delusions or both delusions and hallucinations were excluded based on prior research. Patients were assessed clinically for the presence of hallucinations using the DSM-IV glossary definitions. They were also rated on standardized measures of cognitive impairment, depression, functional impairment, and general health.

Results: There was a significant association between hallucinations and race in patients with Alzheimer's disease. Before adjustment for other variables, the African-American race conferred a 5.5-fold (95% CI = 1.4-21.6; p = 0.02) increased risk for isolated hallucinosis. After adjustment for multiple other variables, this risk increased further to 27.2-fold (95% CI = 1.6-457.3; p = 0.02).

Conclusions: African-American patients with Alzheimer's disease are more likely to have isolated hallucinations than Caucasian patients even after statistical adjustment for multiple confounding variables, which might distort this association. This finding has implications for our understanding of the etio-pathogenesis of hallucinations in Alzheimer's disease and for meeting health service needs of African-American patients.