For years, more boys than girls have taken their own lives — but that divide is narrowing.

And it’s not because fewer boys are dying by suicide. It’s because the number of girls doing so is rising, according to research released Friday by Nationwide Children’s Hospital in Columbus, Ohio.

Suicide is still a leading cause of death among teenagers, but the researchers found a disproportionate increase in the number of suicides by younger girls from the ages of 10 to 14.

“We can’t think it’s just a male problem,” said study author Donna Ruch, a researcher at Nationwide Children’s Center for Suicide Prevention and Research.

Ruch and her colleagues analyzed national data on suicides from 1975 to 2016 among children and teens 10 to 19. Suicide rates fell during the 1990s, but started to climb in 2007, according to the study published Friday in JAMA Network Open. Rates increased among both boys and girls, but more so for girls.

We can’t think it’s just a male problem.

“It’s not just numbers. We’re seeing a trend,” Ruch told NBC News. “But we don’t have good information about what is driving this shift.”

Outside experts suggest part of the reason rates started increasing in 2007 was because of better surveillance and reporting. The CDC’s National Violent Death Reporting System began collecting information on violent deaths, including suicides, from six states in 2002. Other states were gradually added, with data collection rising to all 50 states just last year.

“We’re also treating youth depression less aggressively than we were back in the 1990s,” said Julie Cerel, a psychologist at the University of Kentucky and former president of the American Association of Suicidology.

In 2004, the FDA added a black box warning to antidepressants, indicating the drugs are associated with an increased risk for suicidal thoughts in young people. Cerel said that deterred some parents and doctors from giving the medications to teenagers.

Experts agree more research is needed. “We’re all trying to figure out what we’re missing and how to do a better job at keeping these kids alive,” Cerel said.

“Is it bullying? Social media? Specific entertainment shows? With suicide it’s never just one cause,” Cerel added. “But at the same time, it’s hard to figure out how each of those areas play into the pain teenagers are feeling.”

While news of suicides can be upsetting for parents, child psychologists stress that it’s crucial parents talk to their children about it, rather than ignore the trend.

“Have frank conversations about suicide and hopelessness and pain,” Cerel said. “Be able to ask your kids and your kids’ friends: ‘Are you hopeless? Are you thinking of killing yourself?’”

And the earlier parents can open up the lines of communication with their children, the better, according to Cerel. “Kids with thoughts of suicide have said, ‘I first felt like this when I was in preschool,’” she said.

She recommends age-appropriate ways of talking with kids about expressing their feelings.

“Make it a normal conversation very early on, kind of like talking to little kids about stranger danger and inappropriate touching,” Cerel told NBC News.

Ruch agrees. “We need to be able to have intelligent conversations about this with our kids,” she said.

“This could be happening at a much younger age than parents think.”

Some of the typical warning signs for suicidal thoughts and suicide are:

a child or teenager who says they think about killing themselves

a child or teenager who is unhappy for an unusually extended period of time

a child or teenager who withdraws from friends, school or social activities

a child or teenager who is increasingly irritable or aggressive

Parents can find additional resources through a children's mental health program at Nationwide Children's Hospital called On Our Sleeves.

This story discusses suicide. If you or someone you know is at risk of suicide, please contact the National Suicide Prevention Lifeline at 800-273-8255 or text HOME to 741741.

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