Alzheimer’s disease (AD) research shows that those who suffer from depression may have a higher risk of cognitive decline over time. Depressive symptoms, together with brain amyloid, a biological marker of Alzheimer’s disease could trigger changes in memory and other related cognitive decline symptoms.
The research from Massachusetts General Hospital (MGH), published in JAMA Network Open, focuses on the connection of brain amyloid and cognitive decline. Research in the past has primarily focused on the preclinical stage when patients have biological evidence of AD but minimal symptoms. The researchers at MGH saw that this could be a time when interventions might have the potential to prevent the future decline of older adults.
The first study of its kind, the MGH researchers collected data over seven years from 276 older adults. All participants were enrolled in the landmark Harvard Aging Brain Study (HABS). Through this study, it was discovered that there was a significant link between cognitive decline and worsening depression symptoms over two to seven years that was influenced by AD pathology. This was measured by PET imaging of brain amyloid.
“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,” explains Jennifer Gatchel, MD, Ph.D., of the MGH Division of Geriatric Psychiatry, and lead author of the study. “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.”
Other Risk Factors
Researchers did note in the study that not all older adults with depression symptoms and cortical amyloid will experience failing cognition. They concluded that other risk factors could modify the relationship between cognitive decline and depression. This could include brain metabolism and the volume of the hippocampus, the part of the brain associated with learning and forming new memories. Other mechanisms also may be involved such as tau-mediated neurodegeneration, hypertension, hypercortisolemia, and inflammation. More research is needed to further investigate these relationships.
“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,” notes Gatchel. “This is an area we will continue to actively study.”
Depression is common among patients with Alzheimer’s disease. However, it can be hard to know if someone with Alzheimer’s disease is depressed because the two conditions often have many of the same symptoms. There are no concrete ways to keep Alzheimer’s patients from becoming depressed, but studies have shown that good health habits such as eating a balanced diet and getting exercise can go a long way to helping combat the risk of depression.
Although more research is needed, this study opens the door for more studies to focus on the connection between amylase, depression, and cognitive decline. If physicians can detect disease earlier through the appearance of amylase in the brain, they may be able to help deter risk factors for cognitive decline in the future.