This article is more than 5 years old. Information may no longer be current.

Research identifies modifiers of psychosis in Alzheimer's disease

Recent findings suggest that Lewy body dementia pathology and cerebrovascular disease are significant modifiers of psychosis in Alzheimer’s disease.

To determine demographic, clinical and neuropathological features associated with psychosis in Alzheimer’s disease, Corinne E. Fischer, MD, of the Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, and colleagues reviewed two overlapping groups of individuals diagnosed with Alzheimer’s disease. Study participants included clinically diagnosed patients (n = 890) and neuropathologically definite patients (n = 728), regardless of clinical diagnosis. Researchers assessed associations between psychosis and clinical variables, neuropathological correlates and vascular risk factors.

Overall, 34% of clinically diagnosed participants and 37% of neuropathologically definite participants had psychosis symptoms during their illness.

Hallucinations were associated with greater cognitive and functional impairments on the Mini-Mental State Exam and global Clinical Dementia Rating. Participants with delusions exhibited lower impairment on the global Clinical Dementia Rating.

There appeared to be an association between Alzheimer’s disease pathology burden and the presence of psychosis symptoms among clinically diagnosed individuals, according to researchers. However, this association was not confirmed in neuropathologically definite participants, suggesting the finding was due to misdiagnosis of Alzheimer’s disease.

Development of psychosis was associated with Lewy body pathology, subcortical arteriosclerotic leukoencephalopathy and vascular risk factors, including hypertension and diabetes.

“We demonstrated that in the clinically diagnosed [Alzheimer’s disease] population, including false positive diagnosis of [Alzheimer’s disease], psychosis is associated with [Alzheimer’s disease] pathology. However, in the pathologically diagnosed [Alzheimer’s disease] population, psychotic symptoms do not vary with the severity of [Alzheimer’s disease] pathology but instead are associated with [Lewy bodies], subcortical ischemic vasculopathy, and cerebrovascular risk factors including hypertension, smoking and diabetes,” the researchers wrote. “Combined, these findings suggest that [Lewy bodies] and cerebrovascular disease are important risk modifiers of psychosis in [Alzheimer’s disease].” – by Amanda Oldt

Disclosure: The researchers report no relevant financial disclosures.