Meta and TikTok lose appeal as youth addiction cases proceed in federal court, with over 3,000 consolidated cases alleging platform design features encouraged compulsive use and contributed to mental health problems among children and teenagers. The litigation also includes claims against Google and Snap, with plaintiffs arguing that social media companies built features that promoted repeated engagement by young users, leading to mental health harms such as depression and anxiety. States are pursuing separate cases against Meta, accusing the company of unlawfully collecting children’s personal information and including features that encouraged compulsive use among minors.