A new research study says that if the symptoms of depression steadily increase over time in older age, it could indicate early signs of dementia.
The study emphasized that other patterns of symptoms, such as chronic depression, did not appear to be linked to dementia.
The research was published in The Lancet Psychiatry.
For the study, Dutch researchers analysed more than 3,000 adults aged 55 and over living in the Netherlands. All the adults had depression, but had no symptoms of depression at the commencement of the study.
The Dutch study is among the first to look at different patterns of symptoms of depression.
The researchers looked at the different ways in which depression in older adults increased with the passage of time and analysed if this was linked to any risk.
The researchers concluded that the progression of depression in older age could signal the early signs of dementia.
Dr M Arfan Ikram of the Erasmus University Medical Center in Rotterdam said,
“There are a number of potential explanations, including that depression and dementia may both be symptoms of a common underlying cause, or that increasing depressive symptoms are on the starting end of a dementia continuum in older adults.”
He said that the progression of depressive symptoms over time is a better predictor of dementia later in life than other paths of depression.
The results of the study showed that about one in five of people in the group developed dementia.
The researchers concluded that only the group whose symptoms of depression increased over time was at increased risk of dementia, while the group that had waxing or waning symptoms of depression was not at increased risk of dementia.
In the participants who experienced low but stable levels of depression, around 10% went on to develop dementia.
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Dr Simon Ridley, director of research at Alzheimer’s Research UK, said,
“The findings suggest that low levels of depression or fluctuating symptoms may not affect dementia risk but that a worsening of symptoms in the over-55s may be an early indicator of diseases like Alzheimer’s,” he said.
“It’s important to remember that only a relatively small number of people experiencing symptoms of depression went on to develop dementia during this 11-year study, but anyone concerned about either condition should talk to their GP.”
Dr Simone Reppermund from the Centre for Healthy Brain Ageing at the University of New South Wales, Sydney, said more studies were needed to understand the link between depression and dementia.
“A focus on lifestyle factors such as physical activity and social networks, and biological risk factors such as vascular disease, neuroinflammation, high concentrations of stress hormones, and neuropathological changes, might bring new treatment and prevention strategies a step closer,” she wrote in a linked editorial in the journal.