The findings suggest that “relatively subtle, self-reported feelings of social detachment may be among the first symptoms of brain changes due to Alzheimer’s disease prior to the stage of mild cognitive impairment,” wrote Nancy Donovan, M.D., and colleagues from Brigham and Women’s Hospital, Harvard Medical School, and Massachusetts General Hospital.
The researchers analyzed data on 79 older, cognitively normal, community-dwelling participants (average age of 76.4) from the Harvard Aging Brain Study. Specifically, they looked at the association between loneliness, as determined by the three-item UCLA Loneliness Scale, and cortical amyloid burden, measured by positron emission tomography.
Study participants were asked the following three questions: How often do you feel you lack companionship? How often do you feel left out? How often do you feel isolated from others? Each question was scored on a four-point scale: 1, never; 2, rarely; 3, sometimes; or 4, often, with higher total scores indicating greater loneliness.
Amyloid-positive individuals were 7.5 times more likely than those in the amyloid-negative group to be classified as lonely (defined as endorsement of any of the three loneliness items as present sometimes or often); this association remained after controlling for age, sex, symptoms of depression and anxiety, social network, and more. In addition, the association of amyloid burden and loneliness was stronger in carriers of the AD genetic risk factor APOEε4 than in noncarriers, further strengthening the link between AD pathophysiology and loneliness.
“It has been increasingly clear that AD affects more than just cognition and that neuropsychiatric symptoms in cognitively healthy older adults may be prodromal symptoms of AD. … The study by Donovan et al. suggests that there is room for discovery in this area,” Paul Rosenberg, M.D., of Johns Hopkins University School of Medicine wrote in a related editorial. “They found that a feeling of loneliness—not associated with social networks—reflected a potential AD biomarker. Perhaps other emotions (fear? existential angst? dread? or more positive emotions) might reflect amyloid burden or other biomarkers of preclinical AD.”
He continued, “In the future, we may be able to develop interventions targeting these novel symptoms; based on this first report of loneliness, such interventions might well be new approaches to cognitive-behavioral therapy rather than medications.”
For related information, see the Psychiatric News article “Automated Speech Analysis May Identify People With Alzheimer’s Disease.”