When a person commits suicide, friends and family are left to mourn and wonder why a life was ended so early, what caused it all? The questions can seem even more unanswerable when the victim is a teenager.

"It's very hard for most of us to believe that a young person would take their life," said Laurie Flynn, director of TeenScreen, a national suicide prevention program.

Suicide is the fourth-leading cause of death among children aged 7-17, according to a new study by the Centers for Disease Control and Prevention and the Department of Justice. Between 1981 and 1998 -- the period of the study -- 20,775 people in that age group committed suicide, compared with 24,000 who died of cancer. Suicide has long been considered a single and inevitably tragic incident. But experts are starting to view suicide as a broad public health issue, rather than as an individual struggle.

Even though youth suicide has become a public health crisis, "the money has lagged behind the research," according to Dr. Lanny Berman, director of the American Association of Suicidology, an advocacy group in Washington. That could change soon, though. In March, Sen. Chris Dodd (D-Conn.) introduced legislation that would provide up to $30 million annually to suicide-prevention programs.

The CDC study also detailed the growing role of guns in both youth suicide and homicides. During the study period, youth suicides increased by 44 percent, with gun-related suicides making up 80 percent of that increase. At the same time, the number of youths who committed murder with a firearm tripled, even as the total number of murders remained constant. This shows, according to the CDC's Dr. Alex Crosby, that suicide is linked to other social ills, like gun violence.

Now that public-health officials have come to understand that the suicide is not just an isolated mental-health issue, they are faced with the challenge of slowing the decades-long rise in youth suicide. In 2001, the U.S. surgeon general released the National Strategy for Suicide Prevention (NSSP), which provided public-health officials with new approaches to addressing the problem. Since then, the Department of Health and Human Services subsequently established an affiliated resource center for the public-health community. One of the main goals of the project is to open discussion among a broad range of academic and medical disciplines. "Mental health, social services, education can all play a role," Crosby said. "This is a societal problem, not just one field."

The NSSP recommends that suicide-prevention programs be implemented as widely as possible. One preventative approach is screening youths who seem particularly vulnerable to suicide. For example, TeenScreen created a survey -- developed at Columbia University in 1991 -- designed for middle- and high-school students that takes only 10 minutes to complete.

In 1991, 2,000 students took the TeenScreen survey. An analysis of the results showed that only 31 percent of those with major depression, 26 percent of those who considered suicide, and 50 percent of those who had attempted to kill themselves were in treatment. Suicide "almost never occurs unless there is a mental disorder present," said Flynn, director of the TeenScreen group at Columbia

About 13,000 students will take the TeenScreen survey in 26 states this year. For the first time since the early 1950s, some data indicate that youth suicide is slowing, says Crosby, and public-health officials are beginning to think they've made inroads. "For a long time, we didn't know much" about suicide, Flynn said. "There was a sense that you can't predict it and can't do anything to stop it."

Each year between 1994 and 2001, fewer families have had to try and answer questions left behind by a suicide. Through increased screening and care for at-risk teens, public-health professionals hope to keep youth suicides on the decline.

"There is still a stigma," Crosby said. "But it really can be prevented."