Surgeon General: Social media should come with a warning label like cigarettes

• Dr. Vivek Murthy said social media is contributing to a mental health "emergency."
• He's calling for a Surgeon General's warning label, which would require congressional action. 
• Murthy said parents shouldn't let their kids have social media until after middle school.

The US Surgeon General says social media should come with a warning label — similar to the ones that appear on cigarette packs.