Depression and Heart Disease: A Vicious Circle

July 4, 2013

Heather Tulloch, PhD, is a Clinical, Health and Rehabilitation Psychologist at the University of Ottawa Heart Institute and an Assistant Professor with the Faculty of Medicine and the School of Psychology at the University of Ottawa. As staff psychologist in the Heart Institute’s Division of Cardiac Prevention and Rehabilitation, she assesses patients for depression, anxiety and other mental illnesses that may need to be treated to help patients better manage their heart disease. She also conducts research on the intersection between mental health, behaviour change and heart health.

The Beat: Is depression common in patients with heart disease?

Dr. Tulloch: Yes, rates of depression in the cardiac population are three to four times greater than in the general population. You’re looking at about a 5 to 10% rate in the general population, but in patients with heart disease, it’s about 25 to 30%.

The Beat: How does depression contribute to the development of heart disease?

Dr. Tulloch: There are two ways: there are the physiologic, or direct ways, and then there are the behavioural ways, which are indirect.

The direct ways depression increases the risk of heart disease include increasing the risk of blood clotting, plaque buildup in the arteries and atherosclerosis. Depression also disrupts immune functioning.

Those are real, direct physiological links. They not only put people at greater risk for developing heart disease, they increase the risk of future heart attacks and death. People who are depressed are about two times more likely to have another heart attack as those who aren’t depressed. This is why we need to intervene early to help them decrease their depression.

The indirect ways are all the behavioural factors. We know that people who are depressed are more likely to smoke. We know that if you’re depressed, you don’t have energy to get out and exercise, or prepare a healthy meal. Patients with depression are also less likely to take their medications as prescribed. In general, they find it more difficult to take care of themselves.

Depressed people also tend to be more socially isolated and have more chronic stress, and that takes us back to the physiologic links: You have more release of stress hormones, which then puts you at higher risk. So it’s sort of this vicious circle.

The Beat: For patients diagnosed with depression after being diagnosed with heart disease, is the depression a consequence of their diagnosis, or is it more likely that it was a contributing factor that then continues to be an issue?

Dr. Tulloch: We see both. We see individuals who have had chronic depression, where they’ve had multiple episodes in the past. And then we see individuals who have never had depression before in their lives, and now this is the first time.

For seemingly healthy patients who get a diagnosis of heart disease, it can challenge their whole concept of themselves: They’re fit, they’re healthy and all of a sudden they’re not—they almost died. That can shake up their sense of self, that core “Who am I?” And losing their sense of control is definitely a factor for some.

There can be interpersonal factors, too: They’re here in a hospital bed and family may or may not be with them. They may have to deal with “I’m alone” or “Who am I important to?” or “Who is important to me?’’ All of a sudden, they can see life differently. They also start to consider existential issues—like “I have a second chance: What am I doing with my life?”

Depression and Heart Disease: The Links

Depression can contribute to the development of heart disease by impacting both the body and behaviour. The direct physiological effects that can raise the risk of heart disease include:

  • Coagulation abnormalities, including increased risk of blood clotting
  • Harmful effects on inflammation, leading to the progression of atherosclerosis
  • Increases in stress hormones
  • Disrupted immune function, which reduces one’s ability to fight germs and viruses

Behaviours and social characteristics that can raise the risk of heart disease include:

  • Poor diet
  • Lack of exercise
  • Poor medication adherence
  • Tobacco use
  • Social isolation
  • Chronic life stress

The Beat: Is depression unrecognized as an important risk factor for heart disease in the primary care community?

Dr. Tulloch: I think family doctors are aware, but I’m not sure they have all the tools to deal with it—they’re not trained to do it themselves. My impression is, they’re expected to do everything for patients, and while they’re conscious that depression is a huge issue, they don’t typically have the time to even broach the subject.

Also, our health care system doesn’t pay for psychological services in the community. In a hospital, it’s covered, but there are relatively few psychologists in hospitals and many cardiac rehab programs don’t have psychologist on staff. If a patient is referred to see a psychologist in the community, unless that patient has insurance, he or she will have to pay out of pocket, and it can be prohibitively expensive for many people.

At the Heart Institute, I work with patients experiencing depression to address issues that prevent them from participating in the rehabilitation program. Bob Pelletier, our social worker, also works with patients who need help adjusting to their cardiac conditions. This may include coordinating with family physicians and psychiatry if we feel patients would benefit from medication.

The Beat: Are you currently doing any research on depression and heart disease?

Dr. Tulloch: We are. We’re looking at patients in our rehabilitation program with so-called type D personality, who tend to both experience a lot of negative emotions and keep those emotions to themselves. We know these patients have an increased risk of cardiac events, as well as poorer recovery and worse quality of life afterward.

We don’t know how this personality type contributes to these worse outcomes after a traumatic event like a heart attack. If we understood what’s preventing these patients from complying with their rehabilitation programs, we could design better treatment strategies for them.

Related Articles