Prolonged use of smartphones and computers may increase the risk of depression and suicide- related behaviours in teenagers, especially girls, a major study warns.
"These increases in mental health issues among teens are very alarming," said Jean Twenge, from the San Diego State University in the US.
"Teens are telling us they are struggling, and we need to take that very seriously," Twenge said.
Researchers studied questionnaire data from more than 500,000 teens.
The study published in the journal Clinical Psychological Science looked at data suicide statistics kept by the US Centers for Disease Control and Prevention.
They found that the suicide rate for girls aged between 13 and 18 years increased by 65 per cent between 2010 and 2015.
The number of girls experiencing so called suicide- related outcomes - feeling hopeless, thinking about suicide, planning for suicide or attempting suicide - rose by 12 per cent.
The number of teen girls reporting symptoms of severe depression increased by 58 per cent.
"When I first saw these sudden increases in mental health issues, I wasnt sure what was causing them," Twenge said.
"But these same surveys ask teens how they spend their leisure time, and between 2010 and 2015, teens increasingly spent more time with screens and less time on other activities," he said.
"That was by far the largest change in their lives during this five-year period, and its not a good formula for mental health," he added.
The researchers returned to the data and looked to see if there was a statistical correlation between screen-time and depressive symptoms and suicide-related outcomes.
They found that 48 per cent of teens who spent five or more hours per day on electronic devices reported at least one suicide-related outcome, compared to only 28 per cent of those who spent less than an hour a day on devices.
Depressive symptoms were more common in teens who spent a lot of time on their devices, as well.
On the positive side, the researchers found that spending time away from screen and engaging in social interaction, sports and exercise, doing homework, attending religious services, etc was linked to having fewer depressive symptoms and suicide-related outcomes.
