Mood Matters: Depression and Dementia Risk

Feeling sad is part of being human—but when sadness sticks around for more than two weeks and starts to interfere with your life, it could be depression. It isn’t about weakness or willpower; it’s a real medication condition caused by changes in brain chemistry. The good news?  Depression is treatable and treating it early could protect your brain from future problems with dementia.

Depression doesn’t just affect your mood; science shows depression can also have lasting effects on the brain itself. When depression goes untreated—especially if it occurs in midlife or is long-term—it can change your ability to think, pay attention and remember information in the short term as well as double your risk of developing Alzheimer’s disease later in life.

Biological changes during depression, such as elevated stress hormones, reduced protective brain chemicals, and even shrinkage in memory-related areas of the brain like the hippocampus, help explain why chronic depression may accelerate brain aging.

If you’re struggling with depression, you’re not alone. More than 25% of adults will experience depression at some point, and effective treatment can make a world of difference. Seeking help is not a sign of weakness - it’s an act of self-care that can improve daily life now and protect your brain health for years to come. In this article, we’ll discuss how depression impacts your brain and what you can do to protect yourself. 

But it's important to remember, this is only one of many modifiable behavioral risk factors for Alzheimer's and dementia. 

If you'd like a personalized plan, daily activities and support to help address all of your most pressing risks, sign up for a 2 week free trial of Mindr. Better brain health starts today. 

How Depression Affects Brain Health

Why does depression raise dementia risk? Researchers have uncovered several ways these two conditions are linked.

First, stress hormones. When life gets stressful, your body releases cortisol—a helpful short-term response. But when cortisol stays high for too long, as in chronic stress or depression, it can damage areas of the brain responsible for memory and learning, such as the hippocampus.

Then there’s inflammation. Normally, inflammation helps the body heal. But long-term low-grade inflammation, often found in people with depression, can quietly harm blood vessels and brain cells. It’s also a known contributor to conditions like Alzheimer’s, diabetes, and heart disease.

Another key player is BDNF—brain-derived neurotrophic factor. This protein helps brain cells grow and connect. People with depression tend to have lower levels of BDNF, which can make the brain less resilient and adaptable. Low BDNF is also seen in Alzheimer’s and other brain diseases.

Finally, depression often changes how people live day-to-day. It can lead to poor sleep, less exercise, unhealthy eating, and less social engagement—all of which the 2024 Lancet Commission lists as modifiable dementia risk factors. In fact, a 2015 meta-analysis of over 35 studies confirmed that depression nearly doubles dementia risk, particularly when it’s untreated in later life.

Connections to Other Risk Factors

Depression rarely travels alone—it often links with other dementia risk factors.

Take social isolation, for example. When you’re depressed, reaching out to others can feel impossible. But regular connection protects the brain, while isolation can speed up decline. Or think about physical activity: when depression makes getting off the couch tough, you lose one of nature’s best antidepressants—exercise. Exercise boosts mood, releases feel-good chemicals, and helps control conditions like high blood pressure and diabetes.

What if you haven’t been very active lately? Don’t worry—it’s never too late to start. Even small daily walks can lift mood and protect brain health. Research out of Johns Hopkins University in 2025 found that older adults saw a big drop in dementia risk by adding modest amounts of exercise. In that study, just 35 minutes of brisk physical activity per week (five minutes a day on average) was linked to a 41% lower risk of developing dementia over several years compared to doing nothing.

Poor sleep and depression also go hand in hand. The connection is so ancient that Greek physicians wrote about it. Fixing your sleep can often improve your mood—and vice versa.

Depression can even affect heart and metabolic health. People with diabetes are nearly twice as likely to have depression. And it’s a two way street - not only does having diabetes increase your risk for depression; having depression also increases your risk for diabetes. People with depression have a 60% higher risk of developing type 2 diabetes than those without depression. Similarly, people with depression are three times more likely to have high blood pressure. It’s all connected—and improving one area often helps the others.

Treatment Helps

Treating depression does more than lift mood—it appears to reduce dementia risk. Research suggests that people with depression who receive appropriate therapy or medication are less likely to develop dementia than those who remain untreated.

Effective treatment can improve memory and concentration, restore healthy sleep patterns, reduce stress, and help you re-engage socially and physically. Therapy, support groups, and medications (like antidepressants) can all play a role. Taking antidepressants is no different than taking medicine for blood pressure- they both help your body heal. And lifestyle habits such as mindfulness, exercise, and structured routines strengthen your brain’s resilience even further.

Brain-Healthy Actions You Can Take

Depression is a highly manageable condition. Taking steps to get the right treatment and living a healthy lifestyle which protects you from depression can also keep your brain free of dementia. Here are a few simple steps you can take to get started on your journey to better mental health.

• Reach out for help: If you’ve been feeling persistently sad, empty, or hopeless, talk to a healthcare provider. Therapy, counseling, or support groups can be highly effective. For some, medication may be recommended. Taking antidepressants is no different than taking medicine for blood pressure; both are significant health conditions which require care. Take the depression screening survey your doctor gives you at your annual physical seriously. It’s a useful tool to help your doctor identify and treat any problems before they get too advanced.

• Stay connected and active: Depression can make it tempting to isolate, but connection lifts your mood and a strong support network can help you through an episode of depression. Research has shown that those with depression feel a stronger sense of well-being and belonging when exposed to a positive social interaction than those without depression. Even small steps - a short daily walk outside with a neighbor, a phone call with a friend - can lift your mood.

• Practice mindfulness and stress reduction: Mindfulness meditation, yoga, tai chi, or simply spending time in nature can help lower stress and improve depressive symptoms. Studies about mindfulness and meditation have increased significantly in recent years with some finding the impact of mindfulness on par with more traditional treatments for depression and anxiety. Pick activities that bring you joy or calm, whether it’s painting, listening to music, or gardening and pay attention to your senses while you live in the moment.

• Build routines: Consistent sleep, meal times, and activity patterns support both mood regulation and brain health. During times of stress, routines can help ground you and provide stability and predictability. 

Interested in changing your habits to improve your brain health? Give Mindr a try - it’s free for 2 weeks. Live the longest, healthiest version of your life. Click here to sign up.

The Bottom Line

Depression is not a personal failing - it’s a health condition that affects both mood and the brain. Left untreated, it can increase dementia risk. But with support and treatment, you can feel better now and give your brain the best chance for a healthy future.

You’ve already taken the first step by learning about the link between mood and memory. If you’ve been diligently doing crossword puzzles or eating superfoods to keep your brain sharp, you’re on the right track. Remember: caring for your mental health is just as important as Sudoku or crosswords. Seeking help is a sign of strength - and one of the best gifts you can give to your brain, your health, and your future self.

What’s Next

The interrelated nature of all of the risk factors of dementia can make addressing them feel like an unsolvable puzzle, especially if you are already struggling with depression. It’s a lot to take in all at once. But you don’t have to do this alone. Mindr can help! With Mindr, you will have access to all of these success boosting tools:

• An easy to follow personalized plan that fits your life

• Complementary plans for your most pressing risk factors

• Daily guidance and reminders so you know exactly what to do each day

• Frequent assessments and tracking so you can see your progress

• A human in the loop to support and encourage you

Many studies, including the U.S. POINTER trial, a study of lifestyle changes conducted by the Alzheimer’s Association, have shown that coaching support and structured intervention plans give people a statistically significant edge over those who are self-guided. 

You wouldn’t still be reading this if having a healthy brain wasn’t important to you. The lifestyle changes that will get you there are within your reach. You have the will, we’ll show you the way - one day at a time. You can do this and we can help.

References

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