The occurrence of suicidal ideation, suicide attempts, major depression, & substance abuse was assessed in a sample of college students. Major depression & substance abuse were independent & interactive risk factors for suicidal ideation & attempts. A prolonged desire to be dead was a more specific risk factor for a suicide attempt than was a thought of suicide. Concludes that suicidal ideation in the presence of major depression &/or substance abuse in older adolescent may be lethal. 22 refs.