The Ancient Greeks understood the mind-body connection long before advances in modern medicine were able to scientifically prove the bidirectional feedback loop summed up in the timeless wisdom of the phrase mens sana in corpore sano (a healthy mind in a healthy body).
The results of a 10 year study comparing the association between depression and cardiovascular disease recently published in the journal Atherosclerosis reaffirm (yet again) the interdependence of having a sound mind in a sound body.
This study compared various risk factors of heart disease caused by depression in relation to four other major risk factors that included:

 smoking cigarettes, high cholesterol levels, obesity, and hypertension (high blood pressure).

Of these four risk factors, the researchers conclude that hypertension and smoking cigarettes increase the risk of heart disease the most. While obesity and high cholesterol increase the risk of cardiovascular disease to approximately the same degree as depression. In a statement, lead author Karl-Heinz Ladwig said,

"We invested a great deal of time in this work, just due to the long observation period. Our data show that depression has a medium effect size within the range of major, non-congenital risk factors for cardiovascular diseases.
Our investigation shows that the risk of a fatal cardiovascular disease due to depression is almost as great as that due to elevated cholesterol levels or obesity.
The results show that only high blood pressure and smoking are associated with a greater risk. Viewed across the population, depression accounts for roughly 15 percent of the cardiovascular deaths.”

For this study, a team of researchers led by Ladwig from the Helmholtz Zentrum München, partnered with colleagues from the Technical University of Munich (TUM) and the German Center for Cardiovascular Disease (DZHK). Their research is based on a prospective population-based data set called the "MONICA/KORA" study that was established in 1984 and is one of the few large studies in Europe that facilitates this type of public health analyses.
As alluded to in my introduction, it's important to note that depression's influence on increased risk of cardiovascular diseases is not a one-way street. The feedback loop between mental health issues and physical health issues is a two-way street that is bidirectional and summed up in the phrase mens sana in corpore sano.
In fact, previous research by Ladwig and his team published in The Lancet found that suffering from cardiovascular disease or a heart attack often leads to depression. This can create a vicious cycle that snowballs out of control by exacerbating depression and risk of heart disease in tandem and creates a downward spiral.

Cardiovascular Disease and Depression Are Both Global Public Health Crises

Cardiovascular disease is the leading cause of death in the United States and many countries around the globe. Depression is the leading cause of disability and a major contributor to the overall global burden of all types of disease. The World Health Organisation (WHO) estimates that 350 million people worldwide are affected by depression. If left untreated, major depressive disorders often lead to suicide.

The findings of the latest research by Ladwig and colleagues are a call to action for health providers and medical experts to keep mental health issues on the front burner when offering prescriptive advice for patients at risk of depression and/or cardiovascular disease. The epidemic of heart disease and depression appear to go hand in hand and create a double whammy.
If you are suffering from depression, please reach out to friends, family, or anyone you trust for personal help. But it's also really important to seek professional help. I've been there myself. In my lifetime, I've experienced two Major Depressive Episodes (MDE) that were totally debilitating and pushed me to the brink of suicide. Without the help of mental health professionals, I probably wouldn't be alive today.

I know from first-hand experience that when someone is in the "blackness within the blackness" of clinical depression it seems as if there will never be sunbeams in your soul again. But the light inside your mind will flicker again—if you hang in there and reach out to other people by asking for help.
My three-step advice to anyone suffering from depression or in suicidal crisis is: 1. Don’t isolate. 2. Reach out. 3. Ask for help. Do whatever you need to do to stay vital until you get yourself back on track. As The Verve sing in "One Day" which is one of my favorite anthems for surviving clinical depression,

 "Tie yourself to the mast my friend and the storm will end." The bottom line: Ride out the storm—but don’t do it alone.