At least a quarter of cardiac patients suffer with depression, and adults with depression are more likely to develop heart disease.
There is now a strong body of evidence showing that, compared with people without depression, adults with a depressive disorder or symptoms have a 64 per cent greater risk of developing coronary artery disease – and depressed coronary artery disease patients are 59 per cent more likely to have a future adverse cardiovascular event, such as a heart attack or cardiac death.
Depression has been shown to have physiological effects that are detrimental to heart health as well as behavioural responses that encourage heart disease. Depressed patients with coronary heart disease have reduced heart-rate variability and have higher levels of blood markers for inflammation and clotting. They are also less inclined to exercise and adhere to cardiac treatment, and more likely to smoke.
But despite the established links, people with heart disease are rarely assessed for signs of psychological illness. Unlike the ongoing assessment and treatment of risk factors such as cholesterol and high blood pressure in those with established heart disease, patients are rarely assessed for depression using measurements such as the Beck Depression Inventory (a 21-item rating inventory that measures characteristic attitudes and symptoms of depression).
Recent research has broadened the link beyond depression to stress and anxiety as precursors to major cardiac events. Researchers from Harvard University used specialised imaging techniques to assess stress-related neurological activity (measured as the ratio of amygdala to background prefrontal cortical activity). The results, published in the Journal of Cardiovascular Imaging, showed a higher ratio for people with depression as well as those with anxiety. The risk of a severe cardiac event was found to be highest in those with both depression and anxiety, which the authors say points to heightened stress-related neurological activity as a probable cause.
Doctors in Canada have responded to the overly disease- specific clinical guidelines which hinder a broader and more holistic approach to patients with both cardiac and mental health conditions. Experts from the Brain and Heart Nexus Research Programme at the University of Ottawa Heart Institute in Ontario, working with patient partners, have published new guidance in the Canadian Medical Association Journal (CMAJ) which recognises the interplay between brain and heart diseases.
“These recommendations recognise the intricate relationship between heart and brain disease and the importance of screening and treatment of the whole person, rather than a siloed approach,” says Dr Peter Liu, a cardiologist at the University of Ottawa Heart Institute, and chair and scientific director of the Brain–Heart Interconnectome, a research initiative of the University of Ottawa funded through the Canada First Research Excellence Fund.
For people with coronary artery disease, the guidance specifically recommends that they be screened for depression using a validated tool such as the Beck Depression Inventory. There is high-quality evidence to support the use of depression screening tools in cardiac patients, the experts say. And the patient panel stressed the importance of communication among healthcare providers to ensure timely mental health support.
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The Canadians also recommended that coronary artery disease patients with depression be treated with evidence-based therapies. The strongest evidence was for the use of selective serotonin reuptake inhibitor (SSRI) antidepressants, while there was also evidence to support the use of cognitive behavioural therapy (CBT) in people with co -existing depression and coronary artery disease.
Interestingly, among a total of 11 brain/heart recommendations published in the CMAJ, the group suggested that people with heart rhythm disorder atrial fibrillation be screened for cognitive decline.
It is clear that our approach needs to change if we are to stop the current practice of siloed medicine that focuses on just one disease target. People with coronary artery disease should be routinely assessed for depression, and patients with depression should be regularly assessed for coronary artery disease risk factors.