Emergency room visits for children who attempted suicide or had thoughts of suicide nearly doubled over a nine-year period in the USA, a new nationwide study found.

There were about 1.12 million visits to emergency departments for children ages 5 to 18 for either suicide attempts or suicidal thoughts in 2015. That was up from 580,000 in 2007, the study says.

Among the disconcerting data, 43% of the visits were for young children – ages 5 to 11.

The findings, published Monday in a research letter in JAMA Pediatrics, are "very disquieting," said Lisa Horowitz, a pediatric psychologist at the National Institute of Mental Health, who is independent of the research team that performed the study.

"It's a stunning statistic," she said. "It's just chilling."

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The researchers collected data from the National Hospital Ambulatory Medical Care Survey, an annual and nationally representative survey by the U.S. Centers for Disease Control and Prevention.

As a percentage of all emergency room visits in that time period for children, visits for suicidal thoughts and attempts rose from 2.17% to 3.5%.

That rate is accelerating, compared with past studies, said Brett Burstein at McGill University, the research letter's lead author.

Burstein said suicide attempts and suicidal thoughts are the most important predictors of death by suicide, which is part of why his team chose to study them.

Looking at emergency room visits – where children could be referred to mental health experts – presents an opportunity to better understand how to care for children who attempt suicide or have suicidal thoughts, he said.

"The overall health care burden is large," Burstein said. The majority of the patients tracked in the data did not go to specialized pediatric centers, and most emergency departments "are not, in general, adequately equipped to deal with this problem," he said.

"They lack the resources to deal with this mental health crisis," Burstein said.

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Stories of hope:

The National Institute of Mental Health identifies suicide as a major public health concern. According to CDC data, it is the second leading cause of death for people ages 10 to 34.

The study published Monday further highlights the need for education and outreach, Horowitz said.

"This is a call to action," she said. Horowitz said all emergency departments should screen children for suicide. Though it is recommended nationally that all medical patients are screened, it's not required, Horowitz said.

Unlike the patients in the study, who were diagnosed at ERs for suicidal thoughts or attempts, many children may be in ERs for unrelated reasons but never go through the screening process, she said.

"It takes a nurse 20 seconds" to ask the four questions in the screening process, and by doing so, they may be able to save a life, Horowitz said.

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"There's this myth that if you ask a child about suicide that you're going to put the thought in their head," she said. "The best way to keep a young person from killing themselves is to ask them directly, 'Are you thinking of killing yourself?' "

Many children are secretive about suicidal thoughts, and opening a conversation with children so they know they have an adult they can trust to talk to about these issues can make a huge difference, Horowitz said.

Beyond better training at emergency departments, there must be more education and discussion around mental health issues throughout a child's life, Horowitz said. Schools could put a stronger emphasis on educating students about mental health.

"Schools are really great about teaching reading, writing and math, but they're not teaching coping strategies," she said.

Resources to get help

Suicide Lifeline: If you or someone you know may be struggling with suicidal thoughts, you can call the U.S. National Suicide Prevention Lifeline at 800-273-TALK (8255) any time of day or night or chat online.

Crisis Text Line provides free, 24/7, confidential support via text message to people in crisis when they dial 741741.

Follow USA TODAY's Ryan Miller on Twitter @RyanW_Miller