Instagram’s chief is facing one of the toughest tests of his tenure, defending the app’s design choices as a jury weighs whether social media has damaged a young woman’s mental health. At the center is a simple but high-stakes question: did Instagram’s features encourage harmful use by children, or is the platform being blamed for deeper problems it did not create.
The trial has turned a long-running public debate over youth, phones, and anxiety into a legal showdown that could shape how apps are built for teenagers. In many ways, the case is less about one company’s public relations and more about who gets to set the rules for how attention, emotion, and profit interact on screens used by children.
The case putting Instagram on trial
The lawsuit now in a California courtroom focuses on a single plaintiff, identified as 20-year-old “K.G.M.,” who says her early use of social media led to addiction and made existing mental health problems worse. She argues that the way Instagram was designed when she was a young teen encouraged her to stay online for long stretches and fed content that deepened her distress, a claim laid out in detail as part of a bellwether case that could influence hundreds of similar suits against Meta and other platforms.
Her lawyers say the biggest social media giants treated young users as test subjects in a race for engagement, pointing to internal metrics that tracked how features affected the time children spent on the app. In court, they have framed the case as part of a broader reckoning over how the biggest platforms operate, describing how companies like Meta and YouTube are now on trial in California for allegedly “addicting the brains of children” and using design that harms children’s mental health, an argument that has been amplified in coverage of the California trial.
Adam Mosseri’s defense of Instagram’s design
Into that charged setting walked Adam Mosseri, the CEO of Instagram, who arrived in Los Angeles to testify as the public face of the app and as one of the most senior executives at Meta Platforms. On the stand, he described his job as balancing growth, user satisfaction, and safety, and he insisted that he supported research into how the app affects young people, telling jurors that he “was a supporter” and “is generally a supporter of research” into these questions, a stance described in detail in accounts of his testimony.
He also defended specific product decisions that have come under fire, including features that some inside Meta Platforms had flagged as risky for younger users. According to one account of internal discussions, the top executive at Meta Platforms’ Instagram stood by the ultimate decision not to introduce a stricter default setting that would have further limited certain features for children younger than 16. In court, he framed those calls as hard trade-offs, not reckless gambles, and said he had been trying to weigh different considerations, including user autonomy and product quality.
Can social media be “clinically addictive”?
One of the sharpest clashes in the courtroom has been over language: whether social media can be “clinically addictive” in the way that drugs or gambling can be. Instagram CEO Adam Mosseri on Wednesday rejected the idea that people could be clinically addicted to social media itself, according to a description of his remarks that highlighted how he pushed back on the plaintiffs’ choice of words while still acknowledging that some people struggle to control their use of the app, a stance recounted in coverage of his comments.
That position fits with Meta’s broader legal strategy, which argues that while some users may have unhealthy relationships with their screens, the science has not settled on a medical definition of “social media addiction” that would justify treating Instagram like a controlled substance. A Meta spokesperson repeated that view in public statements, and in court, the company’s lawyers have argued that the question for the jury in Los Angeles is not whether teens sometimes overuse apps but whether the design of Instagram itself can be blamed for clinically diagnosable addiction, a framing that appeared in detailed reports on how the Instagram chief answered questions.
Inside the courtroom: competing stories about harm
While Mosseri has tried to narrow the conversation to definitions and design, the plaintiff’s lawyers have tried to widen it to the lived experience of a teenager in distress. One of them spent much of his time walking jurors through “K.G.M.”’s health records, emphasizing that she had faced many difficult circumstances and that her mental health struggles worsened as she spent more time on social media, an argument described in coverage that quoted the phrase “social media addicting the brains of children” as a core theme of the plaintiff’s lawyer.
Accounts of the trial also describe how lawyers have highlighted the plaintiff’s age and vulnerability, noting that she first used social media as a young girl and that her problems deepened as she moved into adolescence. Reports on the case say the plaintiff, described as a 20-year-old “K.G.M.,” believes that early exposure to Instagram and other platforms led to addiction and made her mental health problems worse, a story that has been laid out in detail in coverage of the landmark case.
Mosseri’s record and the internal debates
To understand why his testimony matters, it helps to remember who Adam Mosseri is inside Meta’s hierarchy. He is not just a public spokesperson but the head of Instagram and a long-serving executive at Meta Platforms, a role reflected in corporate biographies that present him as the top executive responsible for the app. He has been central to decisions on features like algorithmic feeds, Reels, and parental controls, which is why his emails and internal comments have become exhibits in court.
Reports on the trial describe how lawyers questioned Mosseri about internal warnings and debates over youth safety, including disagreements about how strict default settings should be for teenagers and whether to roll out new protections for children younger than 16. One account explained that Adam Mosseri, the head of Instagram, was expected to testify in Los Angeles as part of a case focused on app design and youth mental health, a proceeding described in detail in a Details of the summary that set up his appearance.
