The increased amount of time spent on device screens could be linked to a rise in symptoms of depression, as well as suicide-related behaviors and thoughts among U.S. teens, a new study suggests.  

The increased screen time, which includes the use of mobile phones, tablets and computers, especially affected teen girls, researchers found.

Researchers analyzed survey data on more than 500,000 American teens, as well as suicide statistics from the Centers for Disease Control and Prevention. The data show that the suicide rate for teen girls (ages 13-18) rose by 65 percent between 2010 and 2015. Suicide-related thoughts and behaviors among teen girls, which can include planning or attempting suicide, increased by 12 percent. Meanwhile, the number of female teenagers reporting symptoms of severe depression rose by 58 percent.

Researchers then looked at the survey data to see if there was a link between the amount of time minors spent in front of screens and the mental health symptoms. They found that 48 percent of teens who spent five or more hours in front of a screen daily reported at least one suicide-related outcome, compared to 28 percent of those who spent less than an hour a day on electronic gadgets. Researchers also found depressive symptoms were more common in teens who spent an increased amount of time in front of screens.

At first, researchers didn’t know what was causing teens to feel depressed or have suicide-related outcomes. However, they noticed that teens had reported in the surveys a change in how they spent their free time. Between 2010 and 2015, teenagers spent more time on electronic devices and less time on other activities. That change was the biggest in the five-year period in the teens’ lives, which is “not a good formula for mental health,” says study author Jean Twenge.

“Teen depression and suicide suddenly increased around 2012, which is the same year that the majority of Americans began to own smartphones,” Twenge, a psychology professor at San Diego State, told International Business Times. “Teens who spent 5-plus hours a day on electronic devices were 71 percent more likely to have at least one suicide-related outcome than those who spent one hour a day.”

Other studies have also suggested that spending more time on social media can lead people to feel unhappy.

The recent findings suggest parents should look into the amount of time their kids spend in front of screens. Researchers say limiting screen-time to one or two hours a day would statistically fall into the safe zone for device usage. They found that doing activities like sports, exercise, homework, attending religious services and interacting with others in-person are linked to fewer depressive symptoms and suicide-related outcomes.

"These increases in mental health issues among teens are very alarming," Twenge said. "Teens are telling us they are struggling, and we need to take that very seriously."

More than 44,000 Americans take their lives each year, making suicide the 10th leading cause of death in the U.S., according to the National Institutes of Mental Health. Suicide is the second leading cause of death among people ages 15-34 and the third leading cause among those ages 10-14.

The study was published in the journal Clinical Psychological Science.