It's not clear whether spending a lot of time on Facebook, Snapchat or Instagram leads to social isolation, or whether the lonely seek solace in social media.
Little Brothers, which operates in San Francisco and several other cities, sends volunteers to brighten up the lives of isolated elderly people, helping them reduce the risk of serious illness.
Loneliness and social isolation can affect health for the worse. A California hospital is training volunteers to provide companionship and friendly assistance.
Loneliness takes a toll on many aspects of health, in part because it activates a fight -or-flight immune response. That may have helped ancestors survive lonely exile, but can slowly kill us today.
Teenagers may not need as much face-to-face interaction as earlier generations to feel connected. And that may explain why a study finds they're not feeling as lonely, either.
Loneliness and isolation often go hand in hand, so teasing out which factor is harder on health isn't easy. But a British study now suggests that, while loneliness may make you unhappy, it's social isolation that could take years off of your life. Discuss (with a friend).