Neurobiology of Psychosis in Alzheimer's Disease

Ryan Darby, MD Vanderbilt University


Bradford Dickerson, MD Massachusetts General Hospital, Harvard Medical School
Michael Fox, MD, PhD Beth Israel Deaconess Medical Center, Harvard Medical School


Delusions and hallucinations commonly occur in Alzheimer’s disease (AD) and related dementias, such as Lewy Body Dementia (LBD), causing considerable distress for patients and families.  The goal of this research is to use different types of brain scans and behavioral tests to determine why these symptoms arise.  Our hope is that understanding why delusions and hallucinations occur will help lead to new treatments for these symptoms in the future. 

Project Details

The goal of this research is to find an explanation for delusions and hallucinations, symptoms which commonly occur in AD and LBD. We are testing the hypothesis that patients who develop these symptoms may have abnormal monitoring of their beliefs and perceptions.  Patients who do not monitor their beliefs appropriately may develop delusions, while patients who do not monitor their perceptions appropriately may be more likely to develop hallucinations.  We plan to test patients with delusions and hallucinations using tasks designed to measure self-monitoring of beliefs and perceptions.  We also plan to get brain scans on patients to determine if abnormalities in specific brain regions occur in patients with hallucinations and delusions, compared to patients without these symptoms.  We think that the monitoring problems, and brain imaging differences, might be different between patients with hallucinations and those with delusions.  This work will hopefully help us to understand why these symptoms occur.  It might also lead to new treatments, which will prove especially helpful if it turns out we need to be treating hallucinations and delusions differently from one another.