Study shows cognitive, functional differences between Alzheimer’s disease with delusions, hallucinations

Among individuals with Alzheimer’s disease, those who experienced hallucinations had greater cognitive and functional impairment than those who experienced delusions, according to data presented at the American Academy of Neurology Annual Meeting.

“It is estimated that 41% of [Alzheimer’s disease] patients develop psychosis over the course of the illness, one-third presenting with delusions and one-sixth presenting with hallucinations,” the researchers wrote. “Psychosis in [Alzheimer’s disease] is associated with increased cognitive and functional decline, and a more rapid disease progression.”

To characterize clinical profiles of Alzheimer’s disease with psychotic symptoms, differentiating between delusions and hallucinations, researchers assessed data from the National Alzheimer's Coordinating Center database for 728 individuals diagnosed with Alzheimer’s disease. Of these, 271 experienced psychoses: 140 experienced delusions, 52 experienced hallucinations and 79 experienced delusions and hallucinations.

Age of death, years of education, ethnicity, sex, functional and cognitive status did not significantly differ between participants with psychosis and those without.

However, participants with psychosis had significantly longer disease duration based on age of clinical onset to age of death.

Participants with hallucinations exhibited increased cognitive and functional impairment, while those with delusions were less cognitively impaired than participants without psychosis.

“The contrast between [Alzheimer’s disease] patients who experienced delusions versus hallucinations has not been previously reported. Subjects with hallucinations had lower cognitive and functional status compared to nonpsychotic subjects, while subjects with delusions had better cognitive status. A possible explanation is that expression of delusions requires some level of cognitive ability, and that delusions diminish with cognition,” the researchers wrote. “Data also show that psychotic subjects in general, and those with delusions in particular, had a slower disease progression, contrary to some literature. The distressing nature of psychotic symptoms may prompt these patients to seek medical attention earlier, creating artificially longer disease duration.” – by Amanda Oldt

Reference:

Qian W, et al. Cognitive and functional differences between delusions and hallucinations in Alzheimer’s disease. Presented at: American Academy of Neurology Annual Meeting; April 15-21, 2016; Vancouver, British Columbia.

Disclosure: Qian reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.