Most teenagers who commit suicide or attempt to do so have received mental health treatment, according to researchers who suggest these adolescents aren’t getting the right care to prevent such action.

Almost 1 in 8 teenagers have persistent suicidal thoughts, 4 percent make plans to commit suicide, and another 4 percent attempt to kill themselves, according to the largest study of suicidal behaviors in U.S. adolescents published in the journal JAMA Psychiatry. Most young people with suicidal behavior have pre-existing mental disorders, the research found.

Suicide is the third-highest cause of death among U.S. teenagers, after accidents and homicides. It accounted for 11 percent of deaths among U.S. youth ages 12 to 19 in 1999 through 2006, the most recent data available. Teenagers aren’t being served effectively by the mental health system and need better prevention strategies, the study authors wrote.

“Mental health professionals are not simply meeting with adolescents in response to their suicidal thoughts or behaviors,” the authors said. Although the research doesn’t show how many suicidal thoughts or behaviors may have been prevented by adequate therapy provided by mental health professionals, “it is clear, though, that treatment does not always succeed.”

The study surveyed 6,483 youth ages 13 to 18. About 9 percent of boys and 15 percent of girls reported having experienced persistent suicidal thoughts at some point. Among girls, 5 percent made suicide plans and 6 percent made at least one attempt to kill themselves.

Study Findings

Among boys, 3 percent made plans to commit suicide and 2 percent carried them out. Boys’ attempts were more fatal than girls’, because they tended to use more lethal methods, such as firearms, the study found.

About one-third of teens with thoughts of ending their lives will develop a suicide plan, according to the study. About 60 percent of those with a plan will attempt suicide, most within the first year after onset of a mental disorder.

Of all the mental disorders, only major depression and dysthymia, a type of chronic depression, predicted a suicide plan. Those two illnesses, as well as attention deficit hyperactivity disorder, conduct disorder, eating disorders and intermittent explosive disorder also suggested a higher risk of suicide attempts.

The authors didn’t say what kind of treatment the teens received or from whom. The study was led by Matthew Nock, a professor of psychology at Harvard University in Cambridge.

To contact the reporter on this story: Elizabeth Lopatto in San Francisco at elopatto@bloomberg.net

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net