Suicide is a major public health problem in the United States. In 2003, suicide was the 11th leading cause of death among adults and accounted for 30,559 deaths among people aged 18 or older. Suicide rates vary across demographic groups, with some of the highest rates occurring among males, whites, and the older population. Suicide also is strongly associated with mental illness and substance use disorders. Individuals who die from suicide, however, represent a fraction of those who consider or attempt suicide. In 2003, there were 348,830 nonfatal emergency department (ED) visits by adults aged 18 or older who had harmed themselves. Research suggests that there may be between 8 and 25 attempted suicides for every suicide death. As with suicide completions, risk factors for attempted suicide in adults include depression and substance use.