US researchers say people who suffer from clinical depression in middle age are more likely to develop dementia and Alzheimer's disease later in life. Previous findings had tied depression to dementia, but couldn't clearly define which of them might develop first. A new study published in the Archives of General Psychiatryhas provide evidence showing that chronic depression may increase the risk of developing dementia in old age. The study included more than 13,000 people who were checked for their mental and physical health in middle age and for symptoms of depression in later years of life. Researchers also examined the participants when they were on average 81 years to define which one had developed dementia or Alzheimer's disease. The results revealed that people who had depressive symptoms in middle age but not later in life were about 20 percent more likely to develop dementia later on. The risk of developing dementia also rose to 70 percent for those who showed clinical symptoms of depression later in life. Analysis of the data showed that participants who had depression symptoms in both middle age and later in life were 3.5 times more likely to develop vascular dementia, a type of dementia caused by impaired blood flow to the brain. The finding suggests that “recurring depression over the life course seems to be triggering vascular changes that puts [people] at risk for vascular dementia," said lead author Deborah E. Barnes of the University of California, San Francisco. “One of our take home messages is that depression in older adults is not something that should be ignored," Barnes added. “Depression is not a normal part of aging. ... Depression can be devastating by itself, but it can also be associated with increased risk of developing dementia and it is likely to a precursor to dementia. Older adults should be followed a little closer to see if they develop these impairments and depression."
