Depression, Mental Illness and Substance Abuse: 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.