A major new study has confirmed that depression—whether it occurs in midlife or later in life—is linked to a higher risk of developing dementia. The research, published in eClinicalMedicine, was led by Jacob Brain and Maha Alshahrani from the University of Nottingham, University of Adelaide, and Curtin University’s Dementia Centre of Excellence in Australia.
Dementia is a growing global health crisis, affecting over 57 million people worldwide. With no cure currently available, identifying and managing risk factors is crucial. This new research shows that treating depression early and consistently may be one way to help reduce the risk of developing dementia later on.
The connection between depression and dementia has been known for some time, but one big question remained: whendoes depression have the most impact? Is it more dangerous when it occurs in midlife—your 40s or 50s—or in later years, such as your 60s and beyond?
To answer this, the researchers gathered all the strongest evidence available. They started with an umbrella review, which means they looked at many high-quality reviews that had already studied the link between depression and dementia.
Then they went even further by extracting and reanalyzing data from the original studies in those reviews. They also included newer research that hadn’t been part of earlier summaries.
This allowed them to compare, in a more detailed and accurate way, how depression at different stages of life affects the risk of developing dementia.
Their findings were clear: both midlife and later-life depression are linked to a higher risk of dementia. While it’s still unclear whether depression causes dementia or is a very early sign of it, the results highlight just how important it is to take depression seriously—at any age.
Jacob Brain, the lead author, explained that this work helps shift how we think about depression. “Our study shows that depression is linked to an increased risk of dementia in both midlife and late life,” he said.
“This highlights the importance of recognising and treating depression across the life course—not just for mental health, but as part of a broader strategy to protect brain health.”
The study also raises an important possibility: depression that appears later in life could actually be an early warning sign of dementia. In other words, if someone in their 60s or 70s develops depression for the first time, it might not just be a mental health issue—it could signal that changes in the brain have already begun.
The biological reasons behind this connection are complex. Depression and dementia may share risk factors like inflammation, changes in blood flow in the brain, hormone imbalances, and genetic influences. Long-term stress or poor mental health may also cause damage to the brain over time, increasing the risk of cognitive decline.
But regardless of the exact causes, this study supports one powerful message: treating depression is not only essential for emotional wellbeing—it may also protect your brain.
In conclusion, this research adds strong evidence to the growing understanding that mental health is deeply connected to brain health.
It calls on public health systems, doctors, and individuals to take depression seriously—whether it occurs in midlife or later in life. And with dementia cases expected to rise in the coming decades, focusing on mental health could be a crucial part of prevention efforts.
If you care about mental health, please read studies about 6 foods you can eat to improve mental health, and B vitamins could help prevent depression and anxiety.
For more health information, please see recent studies about how dairy foods may influence depression risk, and results showing Omega-3 fats may help reduce depression.
The research findings can be found in EClinicalMedicine.
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