Across the country more people are committing suicide, especially teenage girls.

NBC News reported that suicide rates have doubled among girls and hit a 40-year high in 2015. The rate increased by more than 30 percent among teen boys and young men.

“There has been a substantial increase in suicide rates in adolescents aged 15 to 19 between 2007 and 2015,” Centers for Disease Control and Prevention suicide expert Thomas Simon said. “Nationally overall we have been seeing an increase in suicide rates that is pretty pervasive among all age groups.”

What’s causing the uptick in suicide? Experts say it’s the result of several risk factors. Economic recessions can be a factor, which could explain some of the increase in suicide rates. Even children can be affected by economic turmoil or financial stress in a family.

Exposure to violence is another factor, according to the CDC.

“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, anxiety, suicide and suicide attempts,” the CDC says.

So what can be done to reduce suicide rates? Suicide is preventable and friends, family members, teachers and others should be on the lookout for it, Simon told NCB News.

Warning signs to look for 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 you know shows any of these signs, get involved.

“If they are vulnerable, it is important not to leave that person alone,” Simon said.

You can call the  National Suicide Prevention Hotline at 1-800-273-8255 if you suspect someone is in danger. You can also call local law enforcement or 911.

The key is to do something.