Another quote from the same article, a paragraph or two later:
> Of course, these analyses don’t unequivocally prove that screen time causes unhappiness; it’s possible that unhappy teens spend more time online. But recent research suggests that screen time, in particular social-media use, does indeed cause unhappiness. One study asked college students with a Facebook page to complete short surveys on their phone over the course of two weeks. They’d get a text message with a link five times a day, and report on their mood and how much they’d used Facebook. The more they’d used Facebook, the unhappier they felt, but feeling unhappy did not subsequently lead to more Facebook use.
-- https://www.theatlantic.com/magazine/archive/2017/09/has-the...
