Emotional and Behavioral Risk Factors for Alzheimer's Disease

BWH Researchers Identify Loneliness as a Potential Risk Factor for Alzheimer’s Disease

According to researchers at Brigham and Women’s Hospital (BWH), loneliness among older adults might be an early sign of brain changes involved in Alzheimer’s disease.

“We set out to ask whether higher cortical amyloid burden, a marker of preclinical Alzheimer’s disease, was associated with greater self-reported loneliness in older adults with normal cognition. We thought loneliness might be an early signal of this abnormal protein accumulation, because in epidemiologic studies people who are lonely have accelerated cognitive decline,” said study leader Nancy J. Donovan, MD, a psychiatrist in the Departments of Psychiatry and Neurology.

Study Design - UCLA 3-Item Loneliness Scale and PET Imaging

Dr. Donovan and her colleagues performed cross-sectional analyses using data from 79 men and women with an average age of 76, who were participating in the Harvard Aging Brain Study. Loneliness was assessed using the UCLA 3-Item Loneliness Scale, and PET imaging was used to detect the presence of brain amyloid.

After factoring in gender, age, depression, genetics, socioeconomic status, anxiety and the social networks of the participants, results showed that those with preclinical Alzheimer disease were 7.5 times more likely to feel lonely when compared to people who did not show early signs of the disease. The study was published in JAMA Psychiatry in November.

Findings: Loneliness and Amyloid Accumulation Correlation

“It may be that during the process of amyloid accumulation, as older people are beginning to decline cognitively, they are less able to successfully socialize, and become less comfortable and have more anxiety in social situations,” said Dr. Donovan.

With regard to the association’s mechanism, Dr. Donovan noted that it is possible that loneliness in older adults might also signal subtle changes in social perception or social reward. A person’s sense of feeling connected to other people is related to brain function and that could be altered in people who have an abnormal accumulation of amyloid, she said.

Loneliness may be one of a number of emotional and behavioral symptoms related to preclinical Alzheimer’s disease. The association could also work in reverse: loneliness could promote the accumulation of amyloid, or perhaps the two could be occurring simultaneously in a cycle, said Dr. Donovan.

“When I tell researchers in the dementia field about the results, they are very surprised. There is little research thus far that demonstrates direct associations of Alzheimer’s biomarkers with neuropsychiatric symptoms, and the fact that we see this with loneliness is even more startling, because loneliness isn’t a traditional neuropsychiatric symptom,” said Dr. Donovan.

Dr. Donovan noted that not all patients who are lonely will develop Alzheimer's disease, but loneliness or social isolation could be relevant characteristics to monitor in older individuals.

“These emotional and behavioral changes could be indicative of brain changes related to Alzheimer's disease and may be part of a checklist of early signs and symptoms of Alzheimer’s that clinicians may use in the future,” said Dr. Donovan.

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