The Connection between Late in Life Depression and Dementia
Memory trouble, excessive sleeping, decreased interest in hobbies and activities, social withdrawal—all of these are textbook symptoms of depression. They also happen to be hallmark behavioral changes related to many kinds of dementia, including the two most common types: Alzheimer’s disease and vascular dementia.
In fact, the early and middle stages of dementia and depression share so many symptoms that even physicians may find it challenging to differentiate the two, especially because they often co-occur. The undeniable connection between these conditions has spurred a great deal of research in recent years. Much of the scientific debate centers on a quintessential chicken and egg dilemma. Which comes first: depression or dementia?
Which Comes first Depression or Dementia?
The Relationship Between Depression and Dementia in the Elderly
Several studies focused on clarifying the relationship between Depression and Dementia two mental health conditions have shed some light on how depression might affect a person’s risk for cognitive decline.
Scientists from the University of California, San Francisco, found a significant link between vascular dementia, Alzheimer’s and depression. The timing of the onset of depression appeared to be associated with different types of dementia.
For example, individuals whose depressive symptoms emerged in their 40s or 50s with symptoms who persisted later in life were found to have more than a three-fold increase in the risk of developing vascular dementia. Vascular dementia is caused by vascular injuries and/or disease within the brain. This study also found that individuals who presented depressive symptoms later in life (with or without symptoms in midlife) were twice as likely as their non-depressed peers to develop Alzheimer’s.
Additional studies on the connections between vascular disease, depression and neurological changes in the brain have supported these findings.
How Can Depression Affect Memory?
Researchers in 2014 examined negative cognition in people who were formerly depressed and a group who never had depression. People who previously had depression were better at remembering negative adjectives from a selection of words than the group who had never been depressed.
Scientists conducting research in 2007 examined the role of positive memory in mood regulation, finding that depressed people’s moods worsened when encouraged to recall happy memories. When people who were formerly depressed recalled happy memories their sad moods did not change.
In addition, the ruminative thoughts characteristic of the disorder could make it hard for people to concentrate on other tasks. Rumination, or fixating on upsetting situations or events, occupies neural resources that the brain could spend on other things, like memory.
The brain may reveal some clues about depression’s hold over memory. The area of the brain dealing with learning and memory — the hippocampus — is sensitive to stress, and tends to be smaller in people with depression. “Diminished hippocampal volume could explain poor recollection,” says Daniel Dillon, assistant professor of psychiatry at Harvard University.
Effects of Depression on the Brain
Increased inflammation: Depression causes increased inflammatory activation of the immune system, which, in turn, affects all aspects of the nervous system. Long-term inflammation can damage the brain, affecting memory, learning and mood.
Higher cortisol levels: Depressed individuals tend to produce higher amounts of the stress hormone cortisol, which can impair the areas of the brain that are responsible for short-term memory and learning.
Structural brain damage: The hippocampus, the part of the brain responsible for turning information into memories, can be harmed when exposed to extended periods of stress. Chronic depression may also cause structural damage to areas of the brain responsible for executive function, attention and emotional regulation.
Behavioral Effects of Depression on the Brain
The symptoms of Depression and Dementia can mirror each other in many ways.
For example, one of the primary symptoms of depression is an unwillingness to engage in regular activities and socialization opportunities. Social withdrawal and reluctance to participate may lead to an inactive brain and a depressed lifestyle.
Studies have found that loneliness and a lack of social engagement placed individuals age 65 and older at greater risk for developing dementia. This lack of engagement can enhance an individual’s susceptibility to showing signs of dementia, especially when compounded by certain genetic, physiological and environmental factors that have been shown to contribute to cognitive impairment.
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Since depression seems to contribute to dementia and vice versa, it can be difficult to tell exactly what physical and mental health conditions are primarily responsible in your elderly loved one. Knowing the signs and being in touch with your elderly loved one’s Physician will help in addressing depression.
Alliance Home Care Can Help
Alliance Home Care provide a wide range of home care, healthcare, companionship and support for the elderly and their families alike. Keeping in contact and being aware of changes in your elderly loved ones is key to being able to support and address any signs of depression or dementia in your elderly loved one.
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