A California state court on Monday began hearing a closely watched lawsuit that could reshape how U.S. courts treat claims that social media platforms harm young users through addictive design.
The case pits a 20-year-old woman, identified in court records as K.G.M., against Meta Platforms, the parent company of Facebook and Instagram, and Google, which owns YouTube.
At the heart of the trial is a simple but far-reaching question: can Big Tech companies be held legally responsible for alleged mental health harm caused not by user-generated content itself, but by the way their platforms are designed to capture and hold attention? The answer could have sweeping consequences for the technology industry and for thousands of similar lawsuits now winding their way through U.S. courts.
K.G.M. alleges that she became addicted to Instagram and YouTube at a young age due to features intentionally engineered to maximize engagement. According to court filings, she argues that the platforms’ design fueled her depression and contributed to suicidal thoughts, leaving her with lasting psychological harm. She is seeking damages for pain and suffering and has asked the jury to consider punitive damages if it finds the companies’ conduct especially egregious.
The case arrives at a pivotal moment for Silicon Valley. For decades, U.S. internet companies have relied on broad legal protections that shield them from liability for material posted by users. Those protections, rooted in federal law, have helped social media firms defeat a wide range of lawsuits alleging harm caused by online content.
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What makes this case different is its focus on product design rather than individual posts or videos. K.G.M.’s lawyers plan to argue that features such as algorithmic recommendations, notifications, and infinite scrolling were negligently designed to encourage compulsive use, particularly among children and teenagers. They say the companies failed to adequately warn users and parents about the mental health risks associated with prolonged exposure.
If a California jury accepts that argument, it could undermine a cornerstone of the industry’s legal defense and open the door to a new wave of claims asserting that social media platforms are harmful by design.
“This is not about blaming platforms for what users say,” one legal expert familiar with similar cases told Reuters. “It’s about whether the architecture of these products creates foreseeable risks, especially for young people.”
Meta and Google deny the allegations and say they will vigorously defend themselves. In court, the companies are expected to highlight other factors in K.G.M.’s life that may have contributed to her mental health struggles. They also plan to point to investments in youth safety tools, parental controls, and content moderation, while arguing that responsibility for harmful material lies with the users who upload it.
Meta Platforms CEO Mark Zuckerberg is expected to be called as a witness, underscoring the stakes of the trial. Proceedings are expected to run into March.
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Notably, two other major social media companies — TikTok and Snap — previously settled with K.G.M. and are not part of the trial. The terms of those settlements were not disclosed.
The California case is just one front in a sprawling legal battle confronting the tech industry. Google, Meta, TikTok, and Snap collectively face thousands of similar lawsuits in the state, brought by individual users and families who allege harm to children and teenagers.
Beyond state court, the companies are also defending against more than 2,300 related lawsuits consolidated in federal court. Those cases have been filed by parents, school districts, and state attorneys general who argue that social media platforms contribute to a youth mental health crisis. The federal judge overseeing those claims is currently weighing whether the companies’ liability protections apply. If the cases move forward, the first federal trial could begin as early as June.
The trial in California coincides with another landmark case opening the same day in Santa Fe, New Mexico. There, the state attorney general has accused Meta of exposing children and teenagers to sexual exploitation on its platforms and profiting from that exposure. Meta has denied those claims as well.
Together, the cases reflect a broader shift in how governments and courts are scrutinizing the social media business model. Concerns about children’s mental health, online safety, and platform accountability have fueled regulatory efforts far beyond the United States.
Australia and Spain have moved to prohibit access to social media platforms for users under the age of 16, citing the potential harm to minors. Lawmakers in other countries are considering similar restrictions, while regulators in Europe continue to enforce stricter rules under the European Union’s digital laws.
Public health researchers and child advocates argue that legal pressure has become a key lever for change. Studies cited by outlets such as the BBC and the Associated Press have linked heavy social media use among adolescents to higher rates of anxiety and depression, though researchers caution that causation is complex and influenced by many factors.
For now, all eyes are on the California courtroom. The jury will be asked to decide not only whether K.G.M. was harmed, but whether Meta and Google’s design choices were a “substantial factor” in causing that harm. The outcome could redefine the responsibilities of platform designers and alter the risk calculus for an industry built on engagement.