Landmark social media addiction trial reaches closing arguments

Jury to decide if platforms are liable for harms to young users

Mar. 12, 2026 at 3:36pm

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After a month-long trial featuring testimony from addiction experts, therapists, and tech executives like Mark Zuckerberg, closing arguments will be heard in a landmark lawsuit against social media companies Meta and YouTube over alleged harms caused to a 20-year-old plaintiff. The case, along with two others, has been selected as a bellwether trial that could impact thousands of similar lawsuits against social media platforms.

Why it matters

This trial represents a major legal test for the social media industry, as it grapples with growing concerns over the mental health impacts of its platforms, especially on young and vulnerable users. The outcome could set an important precedent and pave the way for further legal action against tech giants.

The details

The plaintiff, identified as KGM or Kaley, alleges that her early use of social media led to addiction and exacerbated her depression and suicidal thoughts. Meta and YouTube have argued that Kaley faced significant mental health challenges before using their platforms, which she turned to as a coping mechanism. YouTube has also argued that it is not a social media platform and its features are not addictive. TikTok and Snap previously settled before the trial began.

  • The trial has been ongoing for about a month, hearing from various experts and executives.
  • Closing arguments are set to begin on Thursday, March 12, 2026.

The players

KGM/Kaley

A 20-year-old woman who is the plaintiff in the landmark lawsuit, alleging social media addiction and mental health harms.

Meta

The parent company of Facebook, which is one of the defendants in the lawsuit.

Google-owned YouTube

Another defendant in the lawsuit, arguing that it is not a social media platform and its features are not addictive.

Mark Zuckerberg

The CEO of Meta, who testified during the trial.

TikTok and Snap

Two other social media platforms that were named as defendants but settled before the trial began.

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What they’re saying

“The core question in the case is whether the platforms were a substantial factor in Kayley's mental health struggles.”

— Paul Schmidt, Lawyer for Meta

“Kaley faced significant challenges before she ever used social media.”

— Paul Schmidt, Lawyer for Meta

What’s next

The jury will begin deliberations after hearing the closing arguments, with their decision potentially impacting thousands of similar lawsuits against social media companies.

The takeaway

This trial represents a high-stakes legal battle over the mental health impacts of social media, with the outcome set to have far-reaching implications for the tech industry and how it approaches user safety, especially for young and vulnerable individuals.