The global annual toll of suicide deaths is nearly 1 million, more than deaths from homicide and war combined. Suicide rates remain high or are increasing in many countries. Over 90% of suicide deaths in the US have a history of mental illness such as depression, bipolar disorder, schizophrenia, or substance abuse. Suicide is the third leading cause of death for those under age 45. Risk factors include mental illness, substance abuse, cultural and social pressures, economic stresses, access to means of suicide, and lack of awareness of treatment options. Prevention requires identifying and treating mental illness, restricting access to lethal means, responsible media reporting, and improving access to healthcare and social support services.