The authors assessed the occurrence of suicidal ideation, suicide
attempts, major depression, and substance abuse in a sample of 424
apparently healthy college students 16-19 years old. Major depression and
substance abuse were independent and interactive risk factors for suicidal
ideation and for suicide attempts; substance abuse had a particularly
deleterious effect on men. A prolonged desire to be dead was a more
specific risk factor for a suicide attempt than was a thought of suicide.
The authors conclude that suicidal ideation in the presence of major
depression and/or substance abuse in older adolescents should call forth
greater concern for lethality.