Feeling low in midlife may be linked to dementia risk, new studies find

New studies reveal a strong link between depression and mood disorders in mid to late life and the risk of developing dementia later on. Experts say early detection could be key

When we think of dementia, we often associate it with memory loss and old age. But what if your emotional health in your 40s and 50s could actually be an early sign of it? Two recent studies have come to a strikingly similar conclusion: mood disorders like depression in mid and later life could be early indicators—or even risk factors—for dementia and other diseases.

 

Let’s break it down.

Study 1: Depression increases dementia risk at any life stage

In a recent study published in eClinicalMedicine, experts reveal that depression at any stage can significantly increase the risk of developing dementia later in life. The study was led by Jacob Brain and Maha Alshahrani from the Institute of Mental Health and School of Medicine at the University of Nottingham, the University of Adelaide, and the Dementia Centre of Excellence at Curtin University in Australia.

 

 

Lead author Jacob Brain said that the study shows depression is linked to an increased risk of dementia in both midlife and late life. “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. By clarifying this timing, our work helps guide future research, treatment, and prevention strategies,” he said.

 

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.”

 

Study 2: Mood disorders after 40 may signal early dementia

According to a separate but equally telling study by Japan’s National Institute of Quantum Science and Technology, individuals who experience mood disorders after the age of 40—including depression and bipolar disorder—may be twice as likely to develop neurodegenerative diseases later in life. Researchers observed that these mood disturbances aren’t just emotional hiccups or the result of life stressors. They might actually reflect underlying neurodegenerative changes already taking place in the brain.

 

The study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, touched upon the presence of abnormal tau protein, which is a hallmark of several neurodegenerative diseases. In patients with symptoms such as delusions and hallucinations, tau protein accumulation was larger in specific regions, such as the striatum and the frontal lobe.

 

Why this matters: Depression is a public health priority

Dementia affects over 57 million people globally. Since there is currently no cure for dementia, identifying and treating risk factors such as depression is an important public health priority.

 

This finding is especially important for India, where both dementia and depression are growing public health challenges. Around 7.4 per cent of Indian adults aged 60 and above are living with dementia, which translates to about 8.8 million people today.

 

At the same time, depression is widespread in India. According to the National Mental Health Survey (2015–16), nearly 15 per cent of Indian adults need mental health support, with depression being one of the most common issues. The situation worsened post-pandemic. Depression not only affects mood and daily functioning but, as the study shows, may also raise the risk of dementia later in life.

 

What you can do: Early action matters for brain health

If you or a loved one has been experiencing persistent sadness, irritability, or mood swings after age 40, it might be time to take it seriously—not just for your emotional well-being, but for your cognitive future too.

 

Here’s what experts recommend:

• Seek early evaluation and treatment for any mood-related symptoms
• Stay cognitively and socially active — brain stimulation is protective
• Adopt a brain-healthy lifestyle: exercise, balanced diet, quality sleep, and stress management

Mental and neurological health is often considered separate. But these new studies make it clear: your mood might be one of the earliest indicators your brain gives you. Listening to it could be your first step toward prevention.

 

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This report is for informational purposes only and is not a substitute for professional medical advice.