- In one landmark study, the continued presence of depression after recovery increased the risk of death (mortality) to 17 percent within 6 months after a heart attack (versus 3 percent mortality in heart attack patients who didn't have depression). Frasure-Smith N, et al. Depression following myocardial infarction: Impact on 6-month survival. JAMA, October 20, 1993. 270(15):1819-1825.