Why Do Depressed People Die Younger? An Inquiry into the Relationship Between Depressive Symptoms and Mortality

Jason Houle, Pennsylvania State University

Many studies have shown a positive association between depressive symptoms and mortality. In this study I extend prior research and test competing hypotheses about the functional form of the depression-death relationship. I use nationally representative longitudinal data from the American’s Changing Lives Survey and discrete time hazard models to estimate the association between depressive symptoms and mortality risk at follow-up, accounting for physical health conditions, health behaviors, personal and coping resources, social support, and life stress. Findings show that physical health conditions and health behaviors fully explain the association between depression and mortality, while stress process variables account for only a small portion of the relationship. Additional analyses modeling change over time suggest that physical health and health behaviors mediate the relationship between depression and death, but pre-existing health conditions do not render the depression-death relationship spurious. Implications and limitations of the study are discussed.