Depression diagnosis at two key life stages linked to higher dementia risk

A new study has found that depression during two particular stages of life may increase the risk of developing dementia.

A number of factors can increase our chances of developing dementia, including age and genetics, and lifestyle choices like smoking and excessive alcohol consumption.

Dementia is a general term for loss of memory, language, problem-solving and other thinking abilities that are 'severe enough to interfere with daily life', according to the Alzheimer's Association, with Alzheimer's being the most common cause.

The brain disorder slowly destroys memory and thinking skills, and is marked by a decline in cognitive functions like thinking, remembering and reasoning.

More than seven million Americans are living with Alzheimer's - a number that's expected to rise to almost 13 million by 2050.

Millions of people are affected by dementia (Tek Images/Science Photo Library/Getty Images)

Around one in nine people age 65 and older has the condition in the US.

A new study has found that depression is not only a mental health condition, but can increase the risk of dementia in later life, too.

In some cases, depression itself could be an early sign of dementia.

Jacob Brain and Maha Alshahrani from the Institute of Mental Health and School of Medicine at the University of Nottingham, University of Adelaide and the Dementia Centre of Excellence at Curtin University in Australia, led the new research, published in eClinicalMedicine.

It found that depression in both mid life - your 40s and 50s - and later life - your 60s and beyond - is linked to an increased risk of dementia.

Depression could be an early sign of dementia (Fotografixx/Getty Images)

The link between depression and dementia is complicated, however, and might involve things like long-term inflammation in the body, problems with how the brain and stress hormones work, changes in blood flow and imbalances in brain chemicals.

Mr Brain said of the study: "This highlights the importance of recognizing and treating depression across the life course, not just for mental health, but also as part of a broader strategy to protect brain health.

"Public health efforts need to place greater emphasis on preventative brain health, including scaling up access to effective mental health care."

He added: “Our findings raise the possibility that depression late in life may not just be a risk factor, but it could also be an early warning sign of dementia beginning to develop.

The findings make depression treatment all the more important (Kupicoo/Getty Images)

"By clarifying this timing, our work helps guide future research, treatment, and prevention strategies."

Researchers assessed previous studies that explored the link between depression and dementia, gathering the best studies that had already combined results from multiple research papers.

Then, they dug deeper by re-checking the original data from those studies and adding in newer studies that had been missed before, for a clearer and more current view.

Brain added: “We specifically focused on the timing of when depression was measured, whether it was measured in midlife or in later life, and calculated how much it increased the risk of developing dementia.

"This essentially allowed us to provide a more accurate and up-to-date picture of how depression at different life stages is linked to dementia risk.”