Sept 30 (Reuters) — Major social media stars including Kim Kardashian, Justin Bieber and Charli D’Amelio are among celebrities whose Instagram followers experience more negative feelings about their self-image, according to internal Facebook (FB.O) research revealed by the Wall Street Journal this week, raising questions about the impact of celebrity culture online.

The Journal released the leaked research slide decks on Wednesday, which served as the basis of articles it published earlier this month saying that Facebook knew its apps harmed the mental health of some teenage girls and young users.

The research, titled “Social comparison on Instagram,” surveyed 100,000 people in March and April 2020 in nine countries, including the United States, Australia and Brazil.