evidence: - Between 25 and 50 percent of people who kill themselves had previously attempted suicide. Those who have made suicide attempts are at higher risk for actually taking their own lives. [...] - 18 percent of undergraduate and 15 percent of graduate students have seriously considered attempting suicide in their lifetimes. Between 40 and 50 percent of these same students report multiple episodes of serious suicidal thoughts.(Drum, Brownson, Burton Denmark & Smith, 2009) [...] - Lifetime rates of having attempted suicide reported by adolescents ranged from 21.8% in girls to 11.8% in boys and from 17.6% of both sexes raised on reservations to 14.3% of both sexes raised in urban areas.