Depression and smoking in coronary heart disease

Objective: This review examines the relationship between depression and smoking in coronary heart disease (CHD). It summarizes relevant findings from general population and smoking cessation studies and discusses the few studies that have investigated whether smoking confounds, mediates, or moderates the effect of depression on cardiac morbidity and mortality. Methods: Qualitative review of research literature. Results: Although many studies of the prognostic importance of depression in CHD have adjusted for smoking, there is no convincing evidence that smoking actually confounds the relationship between depression and CHD. There is also no evidence that smoking moderates this relationship. There is, however, limited evidence that smoking may partially mediate the effect of depression on morbidity and mortality in CHD. Conclusion: We need more research on the relationship between depression and smoking in CHD to develop a more complete model of the mechanisms linking depression to cardiac morbidity and mortality.