In just the five years between 2010 and 2015, the number of U.S. teens who felt useless and joyless — classic symptoms of depression — surged 33 percent in large national surveys. Teen suicide attempts increased 23 percent. What happened so that so many more teens, in such a short time, would feel depressed, attempt suicide and commit suicide? After scouring several large surveys for clues, I found that all of the possibilities traced back to a major change in teens’ lives: the sudden ascendance of the smartphone. Read more at The Washington Post.