Science has found many links between depression and other serious medical illnesses, such as cancer, stroke, diabetes, and heart disease. For example, people who develop depression following a heart attack (myocardial infarction) or chest pain (angina) have an elevated risk of cardiac death or hospital readmission over the following year. In a new study scheduled for publication in the October 15th issue of Biological Psychiatry, researchers report that only episodes of depression that commenced after the coronary event were associated with increased cardiac-related morbidity and mortality, but that this increased risk was substantial.
The authors recruited patients hospitalized for ACS, and evaluated them for both lifetime and current depression. Patients were then followed for one year, with additional assessments of depression and cardiac health. Specifically, they discovered that cardiovascular outcome was not associated with prior or existing depression at the time of hospitalization. In contrast, even after controlling for traditional cardiac risk factors such as age, gender, and smoking status, depression that developed in the month after the ACS event increased the odds of cardiac readmission or death by 7 times.
John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, comments, "Depression may be a 'canary in the coal mine,' a relatively early sign of an inflammatory disease process that contributes to coronary artery disease and other medical illnesses." He adds, "The current study suggests that depression may be heterogeneous with respect to its association with inflammatory disease processes, so it will be very important to develop biomarkers, i.e., objective and quantitative tests that can identify the subtype of depression that is a component of systemic disease processes." Senior authors Gordon Parker and Catherine Owen further discuss: "If confirmed, [this finding] has the potential to greatly enhance the ability of health professionals to identify and allocate resources to those patients who are at the greatest risk. This finding also has the potential to shed light on the mechanisms by which post-ACS depression is associated with reduced survival; an area that is still very poorly understood."
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