Written by: Rob Philibert, MD PhD
Ancient Egyptians regarded the heart as the center of both spiritual and intellectual activity. This belief dominated medical thinking until the time of Galen when the importance of the brain in cognition began to be generally appreciated. Since then, there has been an uneasy tension in our understanding of the relationship between mental and cardiac wellbeing. For example, although “Broken Heart Syndrome”, a condition in which cardiomyopathy occurs as a result of acute stressors such as the loss of a loved one, is well-documented, many clinicians are skeptical of a more general connection between mood and risk for coronary heart disease (CHD).
To a certain extent, these concerns are understandable because the rigorous studies that have been used to link cholesterol levels to risk for CHD are largely absent with respect to behavioral health-related factors. However, the scientific basis for suspecting a link is well-founded. Many of the most prominent neurotransmitters used in the brain and associated with the emotional state including serotonin, acetylcholine, and norepinephrine, are used throughout the cardiovascular system to modulate cardiac tone and rhythm. Furthermore, the brainstem directly regulates blood pressure while the peripheral nervous system regulates heart rate. Therefore, from a systems biology perspective, there is a great deal of circumstantial evidence for suggesting a connection between mood and risk for CHD. But until recently, the large-scale studies capable of establishing a causal link between mood and risk for CHD have been absent.
Due to a convergence of studies from a diverse group of individuals, a better understanding is beginning to emerge. These studies are extremely difficult to conduct. Although there are a plethora of self-report surveys to assess mood, these instruments perform poorly and often failed to identify the most severely depressed individuals. Furthermore, medications used to treat depression may affect physiological variables such as blood pressure or cholesterol levels that in turn predict risk for CHD. Nevertheless, using complex meta-analytic methods and data from nearly 1 million subjects, researchers have convincingly demonstrated that the presence of depression increases the subsequent risk for CHD. The real question for researchers is “how”?
From a strict causality perspective, defining the “how” will be difficult. Accurately characterizing both mood and key physiological parameters for research studies is both expensive and difficult to perform. In addition, many risk factors for CHD tend to migrate together making disentangling their effects and identifying unique pathways an arduous task. For example, those with depression have a higher rate of smoking, which is a well-known risk for CHD. However, both smoking and depression are associated with heavy alcohol intake which itself is associated with risk for cardiovascular illness. Finally, each of these 3 factors is associated with a sedentary lifestyle and poor dietary habits. It is literally a Gordian knot of a host of risk factors for CHD whose independent effects are difficult to disentangle.
Fortunately, it is not necessary to fully understand the relationship between depression and subsequent risk for CHD to improve CHD prevention. Depression can be effectively treated through both pharmacologic and psychotherapeutic approaches. Furthermore, while addressing mood symptoms, often operating with the mantra that “a healthy body leads to a healthy mind,“ good mental health practitioners often address more global health concerns such as the risk for hypertension and the need for routine exercise during clinic visits with their patients. Addressing the needs of the entire patient, and not just of the organs above the shoulders makes good clinical sense.
Similarly, our team at Cardio Diagnostics Inc is passionate about more holistic approaches to assessing risk for CHD. Our Epi+Gen CHD, which was named BioTech Breakthrough’s Clinical Diagnostics Solution of the Year, uses the information from three epigenetic assays to assess multiple pathways affecting your risk for CHD-not just cholesterol levels. Take from an expert, and decrease your anxiety by getting a state-of-the-art in CHD risk assessment. Get Epi+Gen CHD.
Resources:
- https://pubmed.ncbi.nlm.nih.gov/11618827/#:~:text=Galen%20considered%20that%20common%20sense,by%20the%20heart%20and%20liver).
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1847940/
- https://bmcpsychiatry.biomedcentral.com/articles/10.1186/s12888-014-0371-z#:~:text=The%20results%20of%20our%20meta%2Danalysis%20of%2030%20prospective%20cohort,30%25%20for%20CHD%20and%20MI.
- https://www.cambridge.org/core/journals/psychological-medicine/article/evidence-for-causal-effects-of-lifetime-smoking-on-risk-for-depression-and-schizophrenia-a-mendelian-randomisation-study/AA82945360EC59FEC4331A7A567309C9
- https://www.sciencedirect.com/science/article/pii/S0167527312000484