Trials are now underway against Meta, YouTube and other social media platforms over allegations that they deliberately designed addictive features and failed to protect children from sexual predators and harmful content. The lawsuits, filed in Los Angeles, New Mexico and other jurisdictions, represent the largest legal reckoning yet with the tech industry over its effects on minors’ mental health — a comparison plaintiffs draw to tobacco and opioid litigation. Meta Chief Executive Mark Zuckerberg testified in the Los Angeles trial on Wednesday.

The trials test a central legal question: whether social media companies can be held liable for designing features they knew would addict children. Success could reshape how platforms operate, force transparency about their algorithms, and challenge the legal shields tech companies have relied on.

In a landmark case in Los Angeles, Meta and YouTube are defending against allegations from a 20-year-old identified as “KGM,” whose case has been selected as a bellwether trial to potentially determine the outcome of thousands of similar lawsuits. The trial features competing narratives: plaintiffs’ attorneys argue that the platforms deliberately designed addictive features while prioritizing growth and engagement over child safety; the companies maintain that plaintiffs faced numerous other challenges before and during their social media use.

The Trials Taking Shape

Meta Chief Executive Mark Zuckerberg testified in the Los Angeles trial on Wednesday, mostly sticking to previous company positions. When plaintiff’s attorney Mark Lanier asked whether people tend to use something more if it’s addictive, Zuckerberg said, “I’m not sure what to say to that. I don’t think that applies here.” On the question of age verification, Zuckerberg said “I don’t see why this is so complicated,” reiterating that the company’s policy restricts users under 13 and that it works to detect and remove users who have lied about their age.

A separate trial in New Mexico focuses on sexual exploitation of minors. New Mexico Attorney General Raúl Torrez, who sued Meta in 2023, built the case by posing as children on social media and documenting sexual solicitations, along with Meta’s response to them. “Meta clearly knew that youth safety was not its corporate priority — that youth safety was less important than growth and engagement,” prosecuting attorney Donald Migliori told the jury in his opening statement. Meta’s attorney Kevin Huff countered that the company has made substantial efforts to remove harmful content, though acknowledged that some dangerous material still reaches users.

A third major trial involving school districts from across the United States is scheduled for this summer before U.S. District Judge Yvonne Gonzalez Rogers in Oakland, California. Jayne Conroy, a lawyer on the plaintiffs’ team, previously represented clients suing pharmaceutical companies over the opioid epidemic. She framed both cases around the concept of addiction. “With the social media case, we’re focused primarily on children and their developing brains and how addiction is such a threat to their well-being,” Conroy said. “The medical science is not really all that different from an opioid or heroin addiction. We are all talking about the dopamine reaction.”

The cases could potentially challenge two major legal protections that tech companies have relied on: the First Amendment and Section 230 of the Communications Decency Act, which shields platforms from liability for content posted by users. If successful, the lawsuits could force companies to change how they operate — altering algorithms, implementing more effective age verification, or changing business models that depend on user engagement metrics.

The Addiction Question

At the heart of these legal challenges lies a more fundamental scientific question: whether social media platforms are truly addictive. Social media companies have disputed this claim, and some researchers question whether addiction is the appropriate term for heavy social media use. During the Los Angeles trial, Zuckerberg stated that the existing body of scientific work has not proven that social media causes mental health harms. Social media addiction is not recognized as an official disorder in the Diagnostic and Statistical Manual of Mental Disorders, the standard reference used by psychiatrists.

Emarketer analyst Minda Smiley noted that while Meta has rolled out safety features in response to mounting concerns, recent reports suggest the company continues to aggressively target teenagers as a user base and does not always adhere to its own safety rules. With appeals and potential settlements, the cases could take years to resolve. Unlike in Europe and Australia, tech regulation in the United States has proceeded slowly, though there is momentum at the state and federal level for action.

Those bringing these cases view this moment as pivotal. Matthew Bergman, director of the Seattle-based Social Media Victims Law Center, which represents more than 1,000 plaintiffs in social media lawsuits, characterized it as such: “This is a monumental inflection point in social media. When we started doing this four years ago no one said we’d ever get to trial. And here we are trying our case in front of a fair and impartial jury.”