"41 Suicidal behavior is complex. Some risk factors vary with age, gender, or ethnic group and may occur in combination or change over time. Suicide is a major, preventable public health problem. In 2007, it was the tenth leading cause of death in the U.S., a ccounting for 34,598 deaths. The overall rate was 11.3 suicide deaths per 100,000 people. An estimated 11 attempted suicides occur per every suicide death. In 2007, suicide was the third leading cause of death for young people ages 15 to 24. As in the g eneral population, young people were much more likely to use firearms, suffocation, and poisoning than other methods of suicide, overall. However, while adolescents and young adults were more likely to use firearms than suffocation, children were dramatica lly more likely to use suffocation. There were also gender differences in suicide among young people, as follows: • Nearly five times as many males as females ages 15 to 19 died by suicide. • Just under six times as many males as females ages 20 to 24 die d by suicide. Research shows that risk factors for suicide include: • depression and other mental disorders, or a substance - abuse disorder (often in combination with other mental disorders). More than 90 percent of people who die by suicide have these ris k factors. • prior suicide attempt • family history of mental disorder or substance abuse • family history of suicide • family violence, including physical or sexual abuse • firearms in the home, the method used in more than half of suicides • incarceration • exp osure to the suicidal behavior of others, such as family members, peers, or media figures. However, suicide and suicidal behavior are not normal responses to stress; many people have these risk factors, but are not suicidal. Research also shows that the r isk for suicide is associated with changes in brain chemicals called neurotransmitters, including serotonin. Decreased levels of serotonin have been found in people with depression, impulsive disorders, and a history of suicide attempts, and in the brains of suicide victims. Public health approaches to preventing suicide include establishing telephone crisis hot lines, restricting access to suicide methods (for example, firearms), counseling media to reduce “copycat” suicides, screening teens for risk fact ors of suicide, and training professionals to improve recognition and treatment of mood disorders. Research about the effectiveness of these methods indicates that the screening and training strategies are more helpful for preventing suicides among young p eople than the other methods are."