August 9, 2019
Increasingly, Alzheimer’s disease research has focused on the preclinical stage, when people have biological evidence of Alzheimer’s but either no symptoms or minimal symptoms—the time when interventions might have the potential to prevent future decline of older adults.
Harvard Medical School researchers at Massachusetts General Hospital have shed new light on this area. Reporting in a study published in JAMA Network Open indicates that depression symptoms in cognitively healthy older individuals, together with brain amyloid — a biological marker of Alzheimer’s — could trigger changes in memory and thinking over time.
“Our research found that even modest levels of brain amyloid deposition can impact the relationship between depression symptoms and cognitive abilities,” said Jennifer Gatchel, HMS assistant professor of psychiatry and a geriatric psychiatrist at Mass General and lead author of the study.
“This raises the possibility that depression symptoms could be targets in clinical trials aimed at delaying the progression of Alzheimer’s disease. Further research is needed in this area,” she said.
Past research has shown an association between depression and cognitive deficits in older individuals. This study, however, is among the first to reveal that this association is influenced by the presence of cortical amyloid in unimpaired older adults, even when depression symptoms are mild to moderate.
Data were collected by researchers over a seven-year period from 276 community-dwelling older adults, all participants in the landmark Harvard Aging Brain Study.
What they discovered was a significant link between worsening depression symptoms and declining cognition over two to seven years that was influenced by Alzheimer’s disease pathology, as measured by PET imaging of brain amyloid.