by: Danling Chen
While clinical depression is classified as a mental illness, it can nonetheless give rise to a number of somatic (physical) symptoms. From headaches to weight loss, depression’s effects on the body are numerous and well documented. Now, according to a study published in the European Journal of Preventive Cardiology, we can count coronary heart disease among the physical conditions with a correlation (but not causative effect!) to depression.
The study, which was conducted by University College London in the United Kingdom, found a potential causal relationship between depression and coronary heart disease. Researchers analyzed 10,308 participants over the course of 20 years, and correlated the results of the participants’ mental health evaluations with their history of heart disease and stroke. They set out to determine whether the severity of depression symptoms had any bearing on cardiovascular health. This is otherwise known as the “dope-response effect."
Their findings indicated that depression did not cause stroke (in fact, they found that there may be a reverse causation relationship, whereby an imminent stroke may cause depression symptoms. However, they concluded that there was a significant potential causal linkage between depression and heart disease. According to Dr. Eric Brunner, clinical depression “accounted for 10% of all [coronary heart disease] events in the study population.” Evidence also supported the existence of a dope-response effect, suggesting that severe depression may indeed be a causal factor in heart disease. (Is was unstated whether mild/moderate depression had any correlation with coronary diseases.)
What are the implications of these findings? While a strong association between depression and heart disease has empirical basis, it still remains to be determined whether depression actually causes heart disease. According to the American Heart Association, heart disease is currently the number one killer. Considering the disease’s prevalence, it is highly likely that a good number of depressed patients will eventually develop heart disease, regardless of their mental health status. Furthermore, heart disease and depression share several risk factors, such as prolonged mental stress, which is definitely not in short supply in today’s society.
So correlation or causation? Future research may be needed to answer that question definitively. Nevertheless, it is a good idea for depressed individuals to pay especial attention to their heart health. Engaging in heart-healthy activities like exercising daily, eating well, and seeing a doctor regularly will have positive physical and mental health consequences. In addition, it’s of note that exercise is considered anti-depressant, so there may be two-fold heart and mind benefits to getting off the couch!
Brunner, E. et al, (2014). Depressive disorder, coronary heart disease, and stroke: dose–response and reverse causation effects in the Whitehall II cohort study. European Journal of Preventive Cardiology, doi: 10.1177/2047487314520785
Whiteman, H. (2014, February 5). "Depression is 'a causal risk of coronary heart disease'." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/272149.
American Heart Association. www.heart.org.