Dementia and depression share many common symptoms: withdrawal from loved ones, decreased interest in activities that were once enjoyable, memory difficulties, and an increase in sleep. Researchers have begun to explore the connection between the two and to ask whether dementia causes depression, or if perhaps depression causes dementia?
One study has found that those who have had a incident of depression are three times as likely to develop dementia. Other studies discovered that when in their life a person experiences depression can influence what kind of dementia they get. Those whose depression begins in mid-life are more likely to get vascular dementia. However, if the episode of depression occurs late in life, Alzheimer’s disease is more likely.
Researchers aren’t sure what causes these links, but they do have some theories. One is that when an individual is experiencing depression, their body produces a greater amount of the stress hormone corisol. This hormone has been shown to do damage to the areas of the brain that manage learning and short-term memory. Depression can also cause inflammation which can harm blood vessels. Finally, there’s also the possibility that the hippocampus, which helps the brain process information and create memories, is harmed when the brain experiences stress long-term. Some even speculate that since depression causes people to be less active both physically and socially, that less challenging lifestyle may accelerate the decay of the mind.
Researchers are very careful to state though that they still have much to learn about this area of study. The connection also seems to work in reverse, with dementia patients being more likely to become depressed after the disease has taken hold. Also, the similarities of the two conditions and the fact that they share many differences make the connection between them difficult to tease out.
One implication that is relatively clear, however: depression needs to be taken seriously and treated as soon as it’s caught. Left alone, it can cause too much damage to an individual’s brain, even if that person eventually moves past depression without intervention. Seniors and their caregivers should know that depression is not a normal sign of aging: it is a mental health issue that needs to be addressed no matter the age of the patient.
This is certainly an area of research to watch over the coming years, and holds promise for helping us understand how conditions of the mind and spirit can ultimately affect the body.