The truth about teens, social media and the mental health crisis

For years, the research picture on how social media affects teen mental health has been murky. That is changing as scientists find new tools to answer the question. (Olivier Douliery /AFP via Getty Images)

Back in 2017, psychologist Jean Twenge set off a firestorm in the field of psychology.

Twenge studies generational trends at San Diego State University. When she looked at mental health metrics for teenagers around 2012, what she saw shocked her. "In all my analyses of generational data — some reaching back to the 1930s — I had never seen anything like it," Twenge wrote in the Atlantic in 2017.