PANews reported on November 23 that, according to Zhitong Finance, in a class-action lawsuit filed by multiple school districts against Meta and other social media platforms in the United States, the full litigation documents revealed that the company halted related internal research after discovering causal evidence that its Facebook and Instagram products had an adverse impact on users' mental health.

Internal Meta documents obtained during the investigation reveal that in a 2020 research project codenamed "Project Mercury," Meta researchers collaborated with Nielsen to assess the impact of discontinuing Facebook and Instagram use. The documents indicate that the results were quite dissatisfying for the company: "Users who stopped using Facebook for a week reported a reduction in depression, anxiety, loneliness, and social pressure." The lawsuit alleges that although Meta's own research confirmed a causal link between its products and users' impaired mental health, the company claimed to Congress that it could not quantify whether its products would harm teenage girls.