Lack of emotional support and social networks can increase the risk of death from medical conditions such as myocardial infarction as much as eightfold, even after adjusting for severity of coronary disease, comorbid conditions, smoking, or hypertension. Lower socioeconomic class has been associated with increased mortality rate independent of other risk factors. The World Health Organization's study of the global burden of disease has estimated that smokers lose, on average, 7.4 years of life. Additional data suggest that smoking also increases the risk of death from various injuries, including suicide and homicide. The literature on substance use disorders suggests a link between substance abuse and increased medical morbidity and early death from accidents, suicide, and homicide. Only with a clearer understanding of the relative importance of the various risk factors can programming toward reducing mortality among people with serious mental illness be implemented.