A Los Angeles jury has found Meta and Alphabet’s Google liable for $3 million in damages in a landmark social media addiction case. The verdict, delivered after more than 40 hours of deliberation, held the companies responsible for the addictive design of their platforms. The plaintiff, a 20-year-old identified as Kaley, said she became addicted to YouTube and Instagram at a young age, worsening her mental health. Meta CEO Mark Zuckerberg and Instagram head Adam Mosseri testified during the trial, while YouTube’s chief executive did not.

Kaley’s legal team argued that features such as notifications and autoplay were intentionally designed to hook young users. Jurors were instructed not to consider user-generated content due to Section 230 protections. Meta maintained that Kaley’s mental health issues stemmed from other causes, while Google argued YouTube is a video platform, not social media. Google said it disagreed with the verdict and planned to appeal. Snap and TikTok had previously settled with the plaintiff before the trial.

Legal experts said the decision could shape future litigation against social media companies, with additional bellwether trials and a federal case scheduled later this year.