One of America's most senior health officials has called on the US government to add smoking-style warning labels to social media websites. Surgeon General Vivek Murthy wants people who uses these sites and apps to be shown a message, warning that they are associated with significant mental health harms for adolescents. Audrey Carville has been speaking about this with leading cyber-psychologist Professor Mary Aiken, and lawyer Paul Tweed, who specialises in defamation cases.