Hypothesis 4. Depression is associated with other physical precipitants of heart disease.

Lesperance F, Frasure-Smith N, Theroux P, Irwin M: The association between major depression and levels of soluble intercellular adhesion molecule 1, interleukin-6, and C-reactive protein in patients with recent acute coronary syndromes. Am J Psychiatry 161:271–277, 2004 Investigators are avidly seeking pathophysiological (or biological) links between depression and coronary heart disease (CHD). Such data would further the status of depression as a modifiable CHD risk factor. In this study, Lesperance et al. determined whether depressed patients with established CHD have higher levels of inflammatory markers following an acute coronary event when judged against comparable nondepressed patients. The development of thrombi from an atherosclerotic plaque leads to a release of cytokines (including interleukin-6 [IL-6]), elevation of serum proteins known as acute-phase reactants (such as C-reactive protein), and the expression and endothelial shedding of soluble intercellular adhesion molecules (such as sICAM-1). These markers tend to be elevated following an acute coronary event, and higher levels predict a worse prognosis.36 The authors wondered whether depression further elevates these markers in patients with recent acute coronary syndromes, thereby increasing the risk for subsequent cardiac events and cardiac-related mortality. Four hundred eighty-one patients from the Montreal Heart Institute referred for a coronary angiogram following a myocardial infarction (MI) or because of unstable angina were assessed for depression. The patients then provided blood samples for measurement of IL-6, sICAM-1, and C-reactive protein. sICAM-1, but not IL-6 or C-reactive protein, was found to differ between depressed and nondepressed patients. The results suggested to the authors that, in patients with a recent acute coronary syndrome, depression is associated with higher degrees of endothelial dysfunction. This relationship remained …