Assessing the Presence and Severity of Depression in Subjects with Comorbid Coronary Heart Disease

Our understanding of how depression alters the origin and course of coronary heart disease is derived from subjective methodologies. Many psychiatric instruments were not tested for reliability and validity in subjects with comorbid medical illness, particularly coronary heart disease. They largely use scales of categoric or ordinal variables. Instruments used to assess coronary heart disease are considerably more objective and often use interval variables. By searching the websites of Circulation and the Journal of the American College of Cardiology, we entered the word “depression” on August 28, 2009. We ignored articles using “depression” in the context of cardiovascular concepts such as “ST-segment depression.” By searching articles dating back to 1995, we selected publications that studied the prognostic association of depression and coronary heart disease. There were 5 relevant publications: 3 from Circulation and 2 from the Journal of the American College of Cardiology. The methods used to assess coronary heart disease (specifically, myocardial infarction) are largely homogenous across the studies, but the methods used to assess depression are heterogeneous. Parameters used to diagnose myocardial infarction and determine its severity are precise, objective, and reliable, whereas those used to assess depression and its severity exhibit less precision and lack comparable objectivity and reliability. This mismatch may compromise our understanding of the link between coronary heart disease and depression in depressed patients with comorbid coronary heart disease. We propose using precise instruments to identify and quantitate coronary heart disease as outcome variables to assess psychiatric interventions and to better define depression in depressed patients with comorbid coronary heart disease. This should lead to a better understanding of the link between depression and comorbid coronary heart disease.