Massachusetts General Hospital (MGH) recently published a study focusing on preclinical stage of Alzheimer’s disease, a stage when no or minimal symptoms and when interventions might have the potential to prevent the future decline of older adults. MGH finds that depression syndromes in cognitively healthy older individuals together with brain amyloid, a biological marker of AD, could trigger changes in memory and thinking over time.
Studies reveal a connection between depression and cognitive defects in older individuals. The MGH study is 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.
MGH collected data over seven years from 276 community-dwelling older adults, all participants in the landmark Harvard Aging Brain Study (HABS). They discovered a significant link between worsening depression symptoms and declining cognition over two to seven years that was influenced by AD pathology, as measured by PET imaging of brain amyloid.
The MGH team also uncovered that not all older adults with depression symptoms and cortical amyloid will experience failing cognition. Other risk factors that can modify the relationship between depression and cognition include brain metabolism and volume of the hippocampus, the part of the brain associated with learning and forming of new memories. Other factors that need further investigation include other mechanisms including tau-mediated neurodegeneration, hypertension, hypercortisolemia, and inflammation.
Jennifer Gatchel, MD, Ph.D., MGH Division of General Psychiatry notes “Our research found that even modest levels of brain amyloid deposition can impact the relationship between symptoms and cognitive abilities.” She continued “These findings underscore the fact that depression symptoms are multi-factored and may actually work synergistically with amyloid and related processes to affect cognition over time in other adults.” She concluded, “This is an area will continue to actively study.”
Jennifer Gatchel, MD, Ph.D., MGH Division of General Psychiatry