Healthy Mind

Cardiac Psychiatrists Unpack the Surprising Relationship Between Mental Health and Heart Health

Photo: Stocksy/Lupe Rodríguez
Colloquially, our minds and our hearts are positioned as total opposites. Being logical is known as "using your head," while making an emotions-based decision is "following your heart." But, according to science, the head and heart may not be operating quite so independently after all. In fact, decades of research has revealed a strong connection between mental health and heart health, such that a substantial drop in either one may be linked with a decline in the other, too.

Perhaps the clearest link between mental health and heart health emerges when you look at the related research on depression. Because depression is one of the most common mental health conditions impacting an estimated 21 million Americans every year, it’s a helpful proxy for thinking about how mental health issues may interact with heart health conditions overall.

The prevalence of depression in folks with heart disease is more than twice as high as it is in the general U.S. population.

“For people who have depression, we know their likelihood of developing heart disease is significantly higher than that of people who don’t have depression,” says cardiac psychiatrist Christopher Celano, MD, director of the Cardiac Psychiatry Research Program at Massachusetts General Hospital. “Research also shows that people who already have heart disease are also at higher risk of developing depression than those who don’t,” he says. Indeed, the prevalence of depression in folks with heart disease is more than twice as high as it is in the general U.S. population (between 20 and 30 percent, in comparison to 7 to 8 percent). For the folks who fall into that camp, outcomes are often worse, too. A January 2022 study found that having a psychiatric condition alongside a chronic disease like heart disease doubles your risk of death.

As a result, experts in cardiac psychiatry—who focus on treating mental health issues in people with existing cardiac diseases—suspect the head-heart connection is bidirectional, with poor mental health potentially worsening heart health, and heart health conditions upping your chances of mental health issues. Though much of the research in this arena centers on depression, there’s also evidence that anxiety disorders, post-traumatic stress disorder, and even chronic stress won’t do your heart any favors, either. And physicians suspect that a few key factors are likely driving the association between mental health and heart health across the board.

How having mental health conditions could increase your risk of heart disease and vice versa

Behavioral pathways

Many studies have shown that making generally health-promoting lifestyle choices—say, eating a nutrient-rich diet and exercising regularly—can substantially lower your chances of getting heart disease. Because having a mental health condition may make you less likely to do all of the above, that’s one major way that it could put you at greater risk.

“We know that people who are depressed or anxious may not do as good a job at taking care of themselves,” says cardiac psychiatrist Peter A. Shapiro, MD, professor of psychiatry at Columbia University Irving Medical Center—likely due to how these illnesses affect a person's energy and executive functioning (aka their ability to plan and complete goals and tasks). “If, for instance, they’re not paying as much attention to what they’re eating, getting enough rest, taking their medications, or exercising regularly, they may be more prone to develop cardiac problems down the line.”

The same thing applies when it comes to the opposite kind of habits with known cardiovascular health risks, says Dr. Celano. Data shows that people with mental health disorders are more likely to smoke and drink—two practices with negative impacts on your heart—which could also help explain the connection between depression and heart health issues.

It’s also likely that certain behavioral tendencies common to folks with heart disease may increase their risk of developing a mental health condition. “You could imagine that somebody with heart disease might be less able to engage in physical activity,” says Dr. Celano. Since physical activity itself is known to have some antidepressant effects, a person in this situation would be missing out on those benefits.

That effect would only be compounded by any of the negative psychological impacts of getting the heart disease diagnosis in the first place, says Dr. Shapiro. “For some people, the stress of having one’s ordinary life role or process disrupted by heart disease may be enough to cause depressive symptoms,” he says. Not to mention, the potential pain and fear involved in having a cardiac event or spending time in the hospital, all of which could increase a person’s risk of mental illness, too.

Physiological pathways

The science on the physiological ties between mental health and heart health is a bit more limited, says Dr. Celano. “Most of the biological links tend to be proven at one point in time, so it’s harder to figure out which direction the relationship is really going.” (In other words, it's unclear if one causes the other, or if any observed biological abnormality is simply a result of having both.)

That said, certain physiological pathways are likely involved in one way or another. For starters, people with depression have been shown to have higher levels of interleukins (proteins produced by white blood cells) in their blood, suggesting higher levels of inflammation that could put them more at risk for heart disease, says Dr. Celano. The reverse may be true, too, as people with severe heart disease also tend to have elevated inflammation levels, which could perhaps contribute to or worsen depressive symptoms, he adds.

People with depression, in particular, are also more likely to experience endothelial dysfunction, “which means that the lining of their blood vessels isn’t as good as it should be at relaxing to allow blood flow to reach the heart,” says Dr. Celano. Without healthy blood flow, the heart can’t do its job as effectively.

Add in the potential cascade of neuroendocrine effects common for psychiatric conditions, and you get yet another interesting link between mental and heart health. “In general, people who are depressed or anxious, for example, tend to experience more sympathetic nervous-system activity [aka fight-or-flight] than parasympathetic [aka rest and digest],” says Dr. Celano. Translation? These folks are likely to experience more frequent spikes in blood pressure and heart rate, and higher levels of cortisol coursing through their bodies than non-depressed people, which can put a lot of extra stress on the heart over time.

Why maintaining good mental health and a positive outlook may help protect your heart

Based on recent research tying optimism with heart health, there’s also something to be said about the unique benefits of a positive psyche for the heart. “We’re seeing that it’s not just the lack of depression that tends to have protective heart benefits,” says Dr. Celano. “There does seem to be a beneficial effect from positive emotions that’s distinct from the negative impact on the heart of feeling depressed.”

Some of that connection is rooted in just the opposite behavioral effect as noted above: Research shows that you’re more likely to engage in heart-healthy behaviors if you’re optimistic. “Specifically, optimistic people are more likely to eat more fruits and vegetables, be more physically active, and take their medications,” says Dr. Celano—all of which is ideal to maintain a well-functioning heart.

It’s also likely that there’s a supportive neuroendocrine link between having a positive outlook and maintaining a healthy ticker. In fact, research on positive affect has shown that it may lead to more parasympathetic (rest-and-digest) activity and lower levels of cortisol, reducing the frequency of blood-pressure and heart-rate spikes as a result.

All of that’s to say, there’s a significant and measurable heart-health benefit to experiencing a positive mental state—which is why Dr. Celano stresses both the importance of seeking treatment for any mental health condition and of finding ways to support your psyche daily, regardless. “Even if you don't have depression, anxiety, or any other mental illness, taking care of yourself, cultivating gratitude, and doing things that feel important and meaningful can really have benefits not only for your emotional well-being but also for your heart,” he says.

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