A new study published in the scientific journal Neurology on July 30 showed that depression is a risk factor for dementia. The results indicate that treating depression in older patients may stave off some of the symptoms of dementia related to thinking and memory skills.

“This is a risk factor we should take seriously,” said lead author Robert Wilson, senior neuropsychologist at the Rush Alzheimer’s Disease Center at Rush University. “Treating depression can reduce the risk of dementia in older people.”

The study followed 1,764 people with an average age of 77, who had no thinking or memory problems at the start of the study. Over a period of nearly eight years, researchers screened study participants for symptoms of depression, while also testing their thinking and memory skills.

During the study, about half the participants developed mild problems with thinking and memory skills, which often act as a precursor to Alzheimer’s disease. 18 percent or 315 study participants developed dementia.

The researchers found that high levels of depression prior to a diagnosis of dementia are linked to a more drastic decrease in thinking and memory skill later on. Overall, depression accounted for a 4.4 percent of the difference in mental decline that could not be attributed to dementia-related damage found in the brain.

However, onset of dementia did not seem to be associated with an increase in depression. In fact, the opposite seemed true.

“We found that people who are developing dementia did not become more depressed as they developed dementia, they actually became less depressed,” Wilson said.

“As people lose their thinking and memory skills, it becomes harder to become depressed and stay depressed. Depression depends on a certain continuity of experience that becomes disrupted as you develop dementia. It’s left to the rest of us to feel depressed as we watch our loved ones slip into dementia.

“We must try to identify structures and functions in the brain that are linked to depression in old age and could help explain depression’s link to dementia. That gives us a better chance of knowing how we should best treat depression in a way that will move the bar and reduce risk of dementia.”

Image via Wikimedia Commons