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The suicide rate among teenage girls continues to rise and hit a 40-year high in 2015, according to a new analysis released Thursday.

Suicide rates doubled among girls and rose by more than 30 percent among teen boys and young men between 2007 and 2015, the updated breakdown from Centers for Disease Control and Prevention finds.

Suicide Rates for Teens Aged 15-19 Years, by Sex -- United States, 1975-2015. CDC

It’s all part of a growing national trend for more suicides, said CDC suicide expert Thomas Simon.

“There has been a substantial increase in suicide rates in adolescents aged 15 to 19 between 2007 and 2015,” Simon said.

“Nationally overall we have been seeing an increase in suicide rates that is pretty pervasive among all age groups,” added Simon. Overall suicide rates have gone up 28 percent since 2000, he said.

The new analysis from the CDC’s National Center for Health Statistics compares recent trends to data going back 40 years. It found the suicide rate for males aged 15 to 19 rose from 12 per 100,000 to 18 per 100,000 men and boys that age between 1975 and 1990. Suicide rates for boys fell between 1990 and 2007 and then started rising again, to 14 suicides for every 100,000 teenage boys by 2015.

“Rates for females aged 15–19 were lower than for males aged 15–19 but followed a similar pattern during 1975–2007,” the NCHS team wrote. “The rate in 2015 was the highest for females for the 1975–2015 period.”

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In 2007, 4,320 children and young adults aged up to 24 died by suicide, the CDC says, making suicide among the top four causes of death for people 10 and up. In 2015, 5,900 kids and adults aged 10 to 24 died by suicide, separate CDC data shows.

“This increase in suicide rate is very concerning,” said Dr. Christine Moutier of the American Foundation for Suicide Prevention.

What’s going on? A lot of different things, Moutier and Simon both said.

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“It is really important to understand that suicide happens as a culmination of multiple risk factors, always multiple, that pile on top and sort of converge at a moment in time,” Moutier said.

Economic recessions can be a big factor, even for kids, said Simon.

“One of the factors that people have talked about as potential contributor to the trend is the economic downturn that we saw in 2007-2009,” Simon said. “As economic problems go up, suicide rates go up.”

Whole families are affected, he said. “There is reason to believe that economic turmoil, financial stresses experienced by parents, can also affect vulnerable youth,” he said.

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Violence is another big factor, the CDC says.

“Exposure to violence (e.g., child abuse and neglect, bullying, peer violence, dating violence, sexual violence, and intimate partner violence) is associated with increased risk of depression, post-traumatic stress disorder (PTSD), anxiety, suicide, and suicide attempts,” the agency says in policy guidance.

Governments can make sure people have somewhere to live and economic support, the CDC advises.

Social media can help or hurt. What’s important is how it’s used, Simon and Moutier said.

"There is a potential for social media to be very helpful in reducing suicide,” Simon said. It can be a great way to get the word out about the signs of suicide risk, and about ways to help, he noted.

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“There is also the potential for it to be harmful,” Simon added.

Cyberbullying is an obvious example, but social media can also spread myths or glamorize suicide.

“On the one hand, kids are at younger and younger ages, are being exposed to all sorts of influences via social media and so, one example that could do harm to a child who is at risk of mental health problems or suicide is that they are experiencing and perceiving themselves and the world around them through a lens that might be distorted by depression,” Moutier said.

Simon said suicide is preventable and parents, friends, teachers and others can be on the lookout for people at risk.

Warning signs for suicide include:

Talking about wanting to die

Talking about feeling trapped

Talking about feeling unbearable pain, or feeling like a burden to others

Acting anxious or agitated

Behaving recklessly

Becoming socially isolated

If someone shows any of the signs, it’s no time to mind your own business, Simon said.

“If they are vulnerable, it is important not to leave that person alone,” he said. One good resource is the National Suicide Hotline at 1-800-273-8255.

“We should be alarmed today, yesterday and every day, because every day on average 16 American youth are taking their lives,” Moutier said.