Report: Meta Buried Evidence of Social Media Harm

Meta buried clear evidence that Facebook use directly worsens users’ mental health, according to internal documents unsealed in a major U.S. lawsuit and revealed in a Reuters investigation published Sunday.

The strongest evidence came from a 2020 experiment called Project Mercury, in which Meta paid Nielsen to run a randomized study: participants who deactivated Facebook for one week reported statistically significant drops in depression, anxiety, loneliness, and harmful social comparison. 

The results showed a causal link — not just correlation — between using the platform and mental health harm.

Meta immediately shut down the project, refused to publish the findings, and told staff the results were unreliable because participants had been “tainted by the existing media narrative” about social media’s dangers, the unsealed filings show. 

One researcher reacted internally by saying the study “does show causal impact on social comparison” followed by a sad-face emoji; another compared the suppression to Big Tobacco hiding smoking risks.

The revelations are part of a 2023 class-action lawsuit by 42 U.S. state attorneys general accusing Meta of addicting children and teens. Despite having this data in hand, Meta executives told Congress in 2021 that the company lacked tools to measure such harms.

Meta has fought to keep the documents sealed and moved to strike them from the record, calling them irrelevant. The company continues to argue that its platforms provide net benefits and that it invests heavily in user safety.