Teenage girls with addiction of relentlessly using smartphones or other digital devices might be at risk of losing sleep and increase in depression, a new Swedish study says. 

The study says teenagers who spend a lot of times glued to their screens tend to get worse sleep, both in terms of sleep quality and duration, researchers wrote in the journal PLOS Global Public Health on Wednesday.

Screen time also prompts teens to delay sleeping until later hours, affecting their sleeping cycles, the study indicates according to UPI. 

Researchers also found that these sleep disturbances are linked to later depression symptoms in girls but not in boys.

“We found that adolescents who reported longer screen times also developed poorer sleep habits over time,” concluded the research team led by Sebastian Hokby, a doctoral student at the Karolinska Institute in Sweden. “In turn, this led to increased depression levels, especially among girls.”

For the study, researchers tracked more than 4,800 Swedish teens between 12 and 16 years of age and collected data on sleep, depression symptoms and screen time at three different points during the course of a year.

They found that depression symptoms among girls were more than twice those of boys, gender difference that has been found in earlier studies, researchers reported.