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New research suggests that there is a strong link between depression and heart disease. Angelos Halaris, M.D., Ph.D., a psychiatrist at the Loyola University Medical Center, is so impressed by the strength of the correlation that he proposes a new medical subspecialty specifically to study and treat combined depression/heart disease patients. The new subspecialty, “Psychocardiology,” would be for the purpose of increasing physician and patient awareness of the strong link between the two disease processes, and would also increase the likelihood that patients with one of the two diseases — who would therefore be at risk of developing the other — would receive appropriate monitoring.
To examine the relationship between depression and inflammation, which is associated with heart disease, Halaris and colleagues examined the blood levels of a chemical called Interleukin 6 (IL6). IL6 triggers inflammation via the sympathetic branch (“fight or flight”) of the nervous system , and is known to be elevated in patients at risk for cardiovascular disease . Halaris’ research showed that patients with major depressive disorder had significantly higher blood levels of IL6 than healthy (non-depressed) individuals.
The link between the two disease processes can be explained qualitatively via stress, which is strongly associated with depression in a reciprocal relationship (depression can increase stress, and stress can lead to depression). Stress also suppresses the immune system and initiates a variety of inflammatory processes in the body, increasing the risk of heart disease.
Dr. Halaris presented his findings at a joint congress of the World Psychiatric Association (WPA), the International Neuropsychiatric Association (INA) and the Hellenic Society for the Advancement of Psychiatry and Related Sciences (HSAPRS) late last year in Athens, Greece.
Though the exact mechanism through which IL6, depression, and heart disease are linked is not completely understood — thereby justifying the need for more research in this area — the correlation between the disease types is strong enough to warrant that patients with depression be monitored closely for heart disease, and vice versa.
According to Dr. Halaris, 40-60% of heart disease patients suffer clinical depression and 30-50% of patients who suffer clinical depression are at risk of developing cardiovascular disease. He proposes that psychocardiology be treated as a multidisciplinary subspecialty where psychiatrists and cardiologists work together. In a Loyola Medicine press release, he stated :
It is only through the cohesive interaction of such multidisciplinary teams that we can succeed in unraveling the complex relationships among mental stress, inflammation, immune responses and depression, cardiovascular disease and stroke.
- Halaris et al. Interleukin-6 as a biomarker in major depressive disorder. Brain, Behavior, and Immunity. Volume 26, Supplement 1, September 2012, Pages S1. PNIRS 2012 — Brain, Behavior, and Immunity in Health and Disease. PsychoNeuroImmunology Research Society’s 19th Annual Scientific Meeting.
- Danesh et al. Long-term interleukin-6 levels and subsequent risk of coronary heart disease: two new prospective studies and a systematic review. PLoS Med. 2008 Apr 8;5(4):e78.
- Loyola Psychiatrist Proposes New Subspecialty for Patients Suffering Depression and Heart Disease. Loyola Medicine. 2013 Feb 18.