February 2007 - A new study by researchers at the Rush Alzheimer's Disease Center,
supported by grants from the Illinois Department of Public Health and the National Institutes on Aging and
published in the Archives of General Psychiatry has found that lonely people may be twice as likely to
develop the type of dementia linked to Alzheimer's disease.
Researchers acknowledge previous studies showing a link between social isolation and increased risk of dementia and decline in cognitive functioning. However, the current study sheds new light on the effects of emotional isolation (or feeling alone) and pays tribute to "the remarkable dedication and altruism" of the volunteers who participated.
Robert S. Wilson, PhD, and colleagues analyzed the association between loneliness and Alzheimer's disease in 823 older adults over a four year period. Participants underwent evaluations including assessments of loneliness, classifications of dementia and Alzheimer's disease, and testing of thinking, learning and memory abilities. Loneliness was measured on a scale of one to five, the score increasing with the degree experienced.
Participants' average loneliness score was 2.3 at first examination. Over the course of the study, 76 individuals developed dementia that met criteria for Alzheimer's disease. Researchers found that the risk for developing Alzheimer's disease increased by approximately 51 per cent for each point scored on the loneliness scale. A person with a high score (3.2) had about 2.1 times greater risk of developing Alzheimer's disease than a person with a low score (1.4). The findings did not change significantly when social isolation indicators, such as a small network and infrequent social activities, were taken into account.
The study concluded that loneliness is a risk factor, not an early sign of Alzheimer's disease. Autopsies performed on 90 individuals who died during the study found no relationship between loneliness and typical brain changes associated with Alzheimer's disease, including nerve plaques and tangles, or tissue damaged by lack of blood flow.
Robert Wilson commented:
"Humans are very social creatures. We need healthy interactions with others to maintain our health. The results of our study suggest that people who are persistently lonely may be more vulnerable to the deleterious effects of age-related neuropathology."
Researchers call for more investigation into how negative emotions cause changes in the brain.
Robert Wilson added:
"If loneliness is causing changes in the brain, it is quite possible that medications or changes in behavior could lessen the effects of these negative emotions and reduce the risk of Alzheimer's disease."
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