False memories not associated with delusions in patients with Alzheimer’s

Key takeaways:

• False memories were not associated with the presence of delusions.
• No overlap was found between brain regions associated with delusions and those associated with false memories.

False memories are not associated with delusions in patients with Alzheimer’s disease, according to a study published in JAMA Psychiatry.

“The findings of this cross-sectional study suggest that despite the superficial resemblances, delusions in AD are more than simply an extension of memory errors or confabulation,” Emma McLachlan, PhD, of the division of psychiatry at University College London, and colleagues wrote. “Furthermore, these findings suggest that psychosis in [Alzheimer’s disease (AD)] is a valid target for pharmacologic and nonpharmacologic treatment approaches and support the existence of a transdiagnostic mechanism for psychosis.”

Using data from the Alzheimer’s Disease Neuroimaging Initiative database, McLachlan and colleagues conducted a study that included 728 participants with an AD diagnosis who had a mean age of 74.8 years.

The mean baseline Mini-Mental State Examination score of patients in the study was 25.1. Delusions were present at baseline in 42 participants and at a later timepoint in an additional 137 participants. The remaining 549 participants comprised the control group. A total of 32 participants with delusions at baseline had a breakdown of psychosis symptoms.

Using the Alzheimer’s Disease Assessment Scale-Cognitive Subscale, the researchers found that the 42 participants with delusions at baseline had higher rates of false recognition than patients in the control group. They additionally found that the false recognition score was inversely associated with left hippocampal volume, right hippocampal volume, left entorhinal cortex volume, left parahippocampal gyrus volume, and left fusiform gyrus volume. However, there was no overlap between brain regions associated with false recognition and those associated with the presence of delusions.

“In line with our hypothesis, the initial results of this cross-sectional study suggested that participants with delusions at baseline had higher rates of false recognition on the ADAS-Cog 13,” McLachlan and colleagues wrote. “However, the association did not survive the inclusion of multiple confounding variables in regression models.”