The first paper is entitled 'Depressive symptoms and risk of dementia: The Framingham Heart Study.'
It is authored by researchers from the University of Massachusetts Medical School (Worcester), Boston University, and Boston University School of Medicine.
According to their paper, they conclude 'Depression is associated with an increased risk of dementia and AD in older men and women over 17 years of follow-up.'
The second paper, which is called 'Recurrent depressive symptoms and the incidence of dementia and mild cognitive impairment, was authored from researchers at the University of Florida, Gainesville.
They conclude, 'Our findings support the hypothesis that depression is a risk factor for dementia and suggest that recurrent depression is particularly pernicious. Preventing the recurrence of depression in older adults may prevent or delay the onset of dementia.'
Page two continues.
The article adds, 'And the researchers stress that the findings merely reveal a link, not a direct cause.'
Dr Jane Saczynski, who led the first (mentioned) study, said: "While it's unclear if depression causes dementia, there are a number of ways depression might impact the risk of dementia.' [BBC News]
The researchers urge that further studies be performed in order to find out why depression and dementia are linked.
Dr. Clive Ballard, who is associated with the Alzheimer's Society, stated that more studies are needed to find out why this link occurs.
He states, 'It is well known depression is common in early stages of dementia. What this study demonstrates is that depression at a younger age is probably a significant risk factor for dementia.' [BBC News]
Page three concludes.
And, also read more about the two conditions at the Mayo Clinic: 'Alzheimer's or depression: Could it be both?'
The May Clinic article states, 'Early Alzheimer's disease and depression share many symptoms, so it can be difficult even for doctors to distinguish between the two disorders. And many people with Alzheimer's also are depressed.'
'One important difference between Alzheimer's and depression is in the effectiveness of treatment. While Alzheimer's drugs can only slow the progression of cognitive decline, medications to treat depression can improve a person's quality of life dramatically.'
'People who have both Alzheimer's and depression may find it easier to cope with the changes caused by Alzheimer's when they feel less depressed.'