WEDNESDAY, Jan. 9 (HealthDay News) -- A new study casts doubt on the value of current professional treatments for teens who struggle with mental disorders and thoughts of suicide.

Harvard researchers report that they found that about 1 in every 8 U.S. teens (12.1 percent) thought about suicide, and nearly 1 in every 20 (4 percent) either made plans to kill themselves or actually attempted suicide.

Most of these teens (80 percent) were being treated for various mental health issues. Yet, 55 percent didn't start their suicidal behavior until after treatment began, and their treatment did not stem the suicidal behavior, the researchers found.

"Most suicidal adolescents reported that they had entered into treatment with a mental health specialist before the onset of their suicidal behaviors, which means that while our treatments may be preventing some suicidal behaviors, it clearly is not yet good enough at reducing suicidal thoughts and behaviors," said Simon Rego, director of psychology training at Montefiore Medical Center/Albert Einstein College of Medicine in New York City.

"It is therefore also important to make sure that mental health professionals are trained in the latest evidence-based approaches to managing suicidality," added Rego, who was not involved in the new study.

According to the U.S. Centers for Disease Control and Prevention, suicide is the third-leading cause of death among adolescents, taking more than 4,100 lives each year.

The report, led by Matthew Nock, professor of psychology at Harvard, was published online Jan. 9 in JAMA Psychiatry.

For the study, researchers collected data on suicidal behaviors among almost 6,500 teenagers.

Fear, anger, distress, disruptive behavior and substance abuse were all predictors of suicidal behavior, they noted.

Some teens were more prone to thinking about suicide than doing it, while others were more concentrated on actually killing themselves, the researchers found.

"These differences suggest that distinct prediction and prevention strategies are needed for ideation [suicidal thoughts], plans among ideators, planned attempts and unplanned attempts," they concluded.

One expert believes the findings must be put into perspective, however.

"It is important to emphasize that the majority of adolescents, and adults for that matter, who think about suicide do not go on to make an attempt, yet ideation is a significant predictor of both plan and attempt," said Lanny Berman, executive director of the American Association of Suicidology.

He noted that the new study found that 40 percent of first suicide attempts by teens were unplanned. That number is "higher than that found among adults (26 percent), reflecting the greater impulsivity of adolescents," Berman said.

Yet little is understood about what drives teens to think about, plan and commit suicide, Berman added.

Clinicians need to appreciate that the majority of those who think about suicide, and who then plan and/or attempt suicide, do so within a year, Berman said.

"In that sense, what we need a greater understanding about is near-term predictors of suicidal behavior -- what is associated with suicide attempts and death by suicide in the next 12 months or, even better, the next 30 days," he said.

In addition, factors associate with suicides aren't always clear, but may involve hopelessness, feelings of meaninglessness, purposelessness or being trapped, insomnia and binge drinking, Berman said.

Also, behavioral clues that signal near-term risk among young people who do not communicate suicide ideation are needed, he said.

More information

For more on suicide, visit the U.S. National Library of Medicine.