Meta accused of burying internal research on mental health harms, Court filing alleges

In a major development in the ongoing U.S. litigation targeting major social media platforms, newly unredacted court filings have revealed allegations that Meta shut down internal research after discovering causal evidence that Facebook and Instagram negatively impacted users’ mental health. The disclosures emerged in a class-action lawsuit filed by multiple school districts across the United States, accusing Meta, Google, TikTok, and Snapchat of concealing known risks associated with their products.

According to the filing submitted late Friday by plaintiffs’ counsel Motley Rice, internal Meta documents obtained during discovery show that the company discontinued a 2020 internal study code-named Project Mercury after researchers found that users who deactivated Facebook and Instagram for one week reported lower levels of depression, anxiety, loneliness, and social comparison. The study, conducted in partnership with survey firm Nielsen, reportedly provided causal evidence that reduced platform usage improved mental well-being.

Rather than publishing the findings or expanding the study, the filing claims, Meta dismissed the results as influenced by negative media coverage and halted further work. However, internal messages cited in the filing suggest staff privately acknowledged the accuracy of the results. One researcher allegedly wrote to former global public policy head Nick Clegg that the study “does show causal impact on social comparison,” while another compared Meta’s reluctance to disclose harmful findings to the tobacco industry’s historical concealment of smoking risks.

Despite internally acknowledging potential harm, the plaintiffs assert that Meta continued to assure U.S. lawmakers it lacked sufficient data to determine whether its platforms negatively affected teenagers, including teenage girls.

In response to the allegations, Meta spokesperson Andy Stone stated that Project Mercury was halted due to methodological flaws and argued that the company has “made real changes to protect teens” over the past decade. He added that the plaintiffs’ claims “rely on cherry-picked quotes and misinformed opinions.”

The lawsuit, brought by school districts nationwide, accuses Meta and its competitors Google, TikTok, and Snapchat of intentionally downplaying and concealing product risks in order to expand youth engagement on their platforms. The plaintiffs argue that schools have been forced to shoulder rising mental health burdens linked to social media use, including anxiety, cyberbullying, and compulsive engagement.

Among the most serious allegations presented in the filing are claims that:

• Meta designed youth safety tools to appear robust but function weakly, allegedly blocking tests of stronger protections that could have reduced user growth.

• Meta set an extremely high threshold 17 violations before removing accounts involved in attempted sex trafficking, according to internal documents.

• Increased teen engagement led to more harmful content, yet product teams continued optimizing for usage rather than safety.

• Child predator protections were delayed for years due to growth concerns.

• Mark Zuckerberg deprioritized child safety, with a 2021 text message quoted in the filing saying it was not his top focus compared to the metaverse.

Stone rejected these assertions and said Meta now removes accounts flagged for sex trafficking immediately and has made teen safety “broadly effective.” The company is also challenging the plaintiffs’ motion to unseal the internal documents, arguing the request is overly broad.

TikTok, Google, and Snapchat have not yet responded to the new filing. However, the plaintiffs say evidence shows that TikTok, for instance, sought influence over child-focused organizations, including the National PTA, by offering sponsorships and expecting favorable public statements in return.

The newly surfaced details are part of a growing body of evidence in the consolidated national litigation accusing major tech companies of harming children’s mental health and misleading the public about safety risks. The underlying documents cited in the filing remain under seal pending a court decision.

A hearing on the matter is scheduled for January 26 in the U.S. District Court for the Northern District of California, where the judge will consider motions related to the unsealing of documents and next steps in the case.