New research finds a sharp rise in suicide rates among children and teens in the month after the release of Netflix's "13 Reasons Why." The series follows the story of a suburban teen who dies by suicide and leaves behind 13 recordings explaining the reasons she killed herself. Some parents and teachers have worried about the possibility of copycat behavior in vulnerable teens.

While the researchers behind the new study cannot prove that the television show is what caused the increase in suicide, they say the association is troubling.

"The graphic portrayal of the main character's death and the way she is memorialized in the show is sending the wrong message," Jeff Bridge, PhD, director of the Center for Suicide Prevention and Research at Nationwide Children's Hospital, said in a statement. "This study should serve as a wake-up call to those creating media that goes against guidelines for how suicide should be depicted."

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For the study, the researchers examined monthly and annual government data on suicide rates among different age groups from the beginning of January 2013 to the end of December 2017. "13 Reasons Why" premiered on Netflix March 31, 2017.

An analysis found that the rates of suicide for 10- to 17-year-olds increased 29% in April 2017, the month following the show's release. Suicide rates for this age group were also significantly higher in June and December of 2017. The increase translated to an additional 195 suicides between April and December of that year, the researchers said.

There were no significant trends in suicide rates in people ages 18 to 64. The study, which was funded by the National Institutes of Health, is published in the Journal of the American Academy of Child and Adolescent Psychiatry.

The researchers were surprised to see that the increase in suicides was driven mainly by boys, when they expected to see an increase for girls, as well. They say future research should look into this disparity.

How suicide is depicted in the media

The National Action Alliance for Suicide Prevention offers recommendations for how suicide should be depicted in movies and television. These guidelines include "conveying that suicide is complex and often caused by a range of factors, rather than by a single event" and "avoiding showing or describing the details about suicide methods."

Major criticisms of "13 Reasons Why" include that it glamorizes suicide and presents it as a way to both end suffering and as a tool for revenge on those who caused hurt to the protagonist.

For its part, Netflix is said it is looking into the latest research. It pointed to another recent study from the University of Pennsylvania that found students who watched the entire second season of the show were less likely to engage in self-harm or seriously consider suicide compared to their peers who did not watch the show.

"It's a critically important topic and we have worked hard to ensure that we handle this sensitive issue responsibly," a Netflix spokesperson told CBS News.

The third season of "13 Reasons Why" is currently in production.

"The results of this study should raise awareness that young people are particularly vulnerable to the media," said study author Lisa Horowitz, a clinical scientist in the National Institute of Mental Health's Intramural Research Program. "All disciplines, including the media, need to take good care to be constructive and thoughtful about topics that intersect with public health crises."

Warning signs of suicide

Experts also urge parents to know the warning signs of suicide, which include:

A person thinking about or threatening suicide or seeking a way to kill themself

Increased substance abuse

Feelings of purposelessness, anxiety, being trapped, or hopeless

Social isolation and withdrawing from people and activities

Expressing unusual anger, recklessness, or mood changes

"If you suspect your child is depressed or is having thoughts of suicide, you should ask the direct question, 'Are you thinking of killing yourself?' The research shows that asking about suicide does not put the thought in a child's head. Rather, it's a question that can save lives," Bridge said.

If the answer is yes, parents should seek immediate medical attention.

For immediate help if you are in a crisis, call the toll-free National Suicide Prevention Lifeline at 1-800-273-TALK (8255), which is available 24 hours a day, 7 days a week. All calls are confidential.