"One of the most telling risk factors for youth is mental illness. Mental or addictive disorders are associated with 90% of suicides. One in ten youth suffer from mental illness serious enough to be impaired, yet fewer than 20 percent receive treatment. In fact, 60% of those who complete suicide suffer from depression. Alcohol and drug use, which clouds judgment, lowers inhibitions, and worsens depression, are associated with 50-67% of suicides."--Jason foundation
Know the signs of risk in your own teen, friend, or student. It is important for teachers to know the signs of suicide. According to the Jason foundation, only twelve states in the United States have mandatory teacher training in suicide awareness. This should be fifty. Check out their site below and find out about mandatory teaching training in suicide awareness. There are many suicide awareness programs on the web, if this one doesn't have what you need look for another one.
http://www.sptsusa.org/ (the society for the prevention of teen suicide)