Loneliness among adolescents around the globe has skyrocketed since a decade ago, reports the Washington Post . And it may be tied to smartphone use, a new study finds:

In 36 out of 37 countries, feelings of loneliness among teenagers rose sharply between 2012 and 2018, with higher increases among girls, according to a report released Tuesday in the Journal of Adolescence. Researchers used data from the Programme for International Student Assessment, a survey of over 1 million 15- and 16-year-old students. The survey included a six-item measure of loneliness at school in 2000, 2003, 2012, 2015 and 2018. Before 2012, the trends had stayed relatively flat. But between 2012 and 2018, nearly twice as many teens displayed high elevated levels of "school loneliness," an established predictor of depression and mental health issues.