Well, here is information every adult should chew on a bit. I might add every parent really needs to read this and proceed to take steps to help their children limit exposure to the many "screens" vying for their attention hour upon hour.
I believe the Lord wants his people to be lifted up in spirit. Generally speaking we should be happy and contented in the Lord. Of course, sadness comes for different reasons. However, sadness should not be self-inflicted by bad habits. Unhappiness caused by Facebook, smartphone usage, etc. can be nipped in the bud!
This article is not a waste of time. Try to glean some wisdom from the research sited in this article.