Depression could increase a person’s risk of developing dementia independently of the biological factors thought to cause the dementia, according to new research published in Neurology today (30 July 2014). The research, led by Rush University Medical School, suggests that older people who had experienced some form of depression were more likely to develop mild cognitive impairment (MCI) – thought to be a precursor to dementia – and dementia.
Researchers at the university studied 1,764 older people without cognitive impairment for an average of 7.8 years. During yearly follow ups the participants were asked a series of questions relating to their mental health including whether they felt lonely on a regular basis. Incident mild cognitive impairment and dementia were associated with a higher level of depressive symptoms before diagnosis but not with a change in symptoms after diagnosis. In post-mortem examinations, the researchers found no association between depressive symptoms and the biological hallmarks which play a role in the development of dementia.
Dr Doug Brown, Director of Research and Development at Alzheimer’s Society commented:
‘We’ve long known that there is a link between depression and dementia but it hasn’t been clear whether depressive symptoms could be early symptoms of the changes occurring in the brain or a risk factor. This interesting study suggests that depression could be a risk factor, separate from the biological processes thought to cause dementia.
This study raises the potential idea that treating depression could be a way to reduce the risk of developing mild cognitive impairment and dementia, but more research is needed in order to test this before we can draw any firm conclusions.