Depression could signal cognitive decline in Alzheimer’s disease

Depressive symptoms might be an early risk factor of developing Alzheimer’s disease before the exhibition of cognitive deficits, a new study shows.

The study, conducted at Massachusetts General Hospital (MGH), demonstrated how depressive symptoms in patients with brain amyloid deposition could impact cognitive abilities among healthy older adults. Although previous research extensively covered the connection between depression and cognitive decline, the new findings are the first to point out its influence on cortical amyloid in healthy older adults, despite minimal depressive symptoms.

As part of the study, published in JAMA Network Open, a team of researchers collected data from 276 older adults over a span of seven years, all of which participated in the Harvard Aging Brain Study. Analyzing this data led the team to the unraveling of a link between declining depressive symptoms and cognitive abilities over a span of two to seven years. The changes, consisting of brain amyloid deposition, were measured through PET imaging.

“Our research found that even modest levels of brain amyloid deposition can impact the relationship between depression symptoms and cognitive abilities. This raises the possibility that depression symptoms could be targets in clinical trials aimed at delaying the progression of Alzheimer’s disease,” said Jennifer Gatchel, lead author of the study.

“Our findings offer evidence that in healthy older adults, depression symptoms together with brain amyloid may be associated with early changes in memory and in thinking,” Gatchel added. “Depression symptoms themselves may be among the early changes in the preclinical stages of dementia syndromes. Just as importantly, these stages represent a clinical window of opportunity for closely monitoring at-risk individuals, and for potentially introducing interventions to prevent or slow cognitive decline.”

“These findings underscore the fact that depression symptoms are multi-factorial and may actually work synergistically with amyloid and related processes to affect cognition over time in older adults. This is an area we will continue to actively study,” Gatchel concluded.