This article in the Atlantic Magazine comprehensively picks over the research, in an attempt to answer this question. I’m not sure there’s anything to be found other than some pretty common-sense generalities, like:
So if social media let you organize a game of football among your friends, that’s healthy. If you turn to social media instead of playing football, however, that’s unhealthy.
What I find more interesting is the way it encourages us to behave in ways that suit the service, but aren’t necessarily in our interests. For example, forever being in a mode of self-presenting:
But the price of this smooth sociability is a constant compulsion to assert one’s own happiness, one’s own fulfillment. Not only must we contend with the social bounty of others; we must foster the appearance of our own social bounty. Being happy all the time, pretending to be happy, actually attempting to be happy—it’s exhausting. Last year a team of researchers led by Iris Mauss at the University of Denver published a study looking into “the paradoxical effects of valuing happiness.” Most goals in life show a direct correlation between valuation and achievement. Studies have found, for example, that students who value good grades tend to have higher grades than those who don’t value them. Happiness is an exception.
We’re adapting ourselves to suit the demands of social media, and we’re not designed to work this way:
Jaron Lanier, the author of You Are Not a Gadget, was one of the inventors of virtual-reality technology. His view of where social media are taking us reads like dystopian science fiction: “I fear that we are beginning to design ourselves to suit digital models of us, and I worry about a leaching of empathy and humanity in that process.” Lanier argues that Facebook imprisons us in the business of self-presenting, and this, to his mind, is the site’s crucial and fatally unacceptable downside.
And it really is a demand:
What’s truly staggering about Facebook usage is not its volume—750 million photographs uploaded over a single weekend—but the constancy of the performance it demands. More than half its users—and one of every 13 people on Earth is a Facebook user—log on every day. Among 18-to-34-year-olds, nearly half check Facebook minutes after waking up, and 28 percent do so before getting out of bed. The relentlessness is what is so new, so potentially transformative. Facebook never takes a break. We never take a break. Human beings have always created elaborate acts of self-presentation. But not all the time, not every morning, before we even pour a cup of coffee.