Facebook's defended itself over a whistleblower's claims that its products "harm children, stoke division and weaken our democracy".
But Mark Zuckerberg says former employee Frances Haugen's testimony to the US senate "just doesn't reflect the company we know".
She told lawmakers Facebook knew it steered young users towards damaging content and that its Instagram app was "like cigarettes" for under-18s.
Dr Mary Aiken is Professor of Cyber Psychology at Capital Technical University in Washington DC.
"In extracts from the Facebook research that the whistleblower made public, it said that teens blame Instagram for the increases in rate of anxiety and depression.
"Also they said they had suicidal thoughts.
"13% of UK users and 6% of US users said that theses impulses could be directly tracked back to the Instagram app."
