Teenage brains were stressed even before smartphones. How can you help your teen handle the strain?

Journalist Matt Richtel sheds light on the teen mental health crisis and what can be done about it in his new book, “How We Grow Up: Understanding Adolescence.”

​ Journalist Matt Richtel sheds light on the teen mental health crisis and what can be done about it in his new book, “How We Grow Up: Understanding Adolescence.” Read More Breaking News, Latest News and Videos | CNN