A United States jury in Los Angeles has found Meta and YouTube liable for harming a young woman due to the addictive design of their platforms.

The verdict was delivered on Wednesday, with the court ordering both companies to pay a total of $6 million in damages, including $3 million in punitive damages.

The jury ruled that both companies were negligent in the design and operation of their platforms, stating that their actions contributed significantly to the harm suffered by the plaintiff.

Jurors also held that Meta and YouTube knew or should have known that their services posed risks to minors but failed to provide adequate warnings.

The court awarded $3 million in compensatory damages, with Meta bearing 70 per cent responsibility, amounting to $2.1 million, while YouTube was assigned 30 per cent, equivalent to $900,000.

In a second phase of the trial, the jury added another $3 million in punitive damages after concluding that both companies acted with malice, oppression or fraud.

Nine out of the 12 jurors supported this finding, strengthening the basis for the additional penalty.

Reacting to the verdict, both companies said they would challenge the decision in court.

“This case misunderstands YouTube, which is a responsibly built streaming platform, not a social media site,” Google spokesperson Jose Castaneda said.

A spokesperson for Meta said they “respectfully disagree with the verdict,” adding that “teen mental health is profoundly complex and cannot be linked to a single app.”

The plaintiff, identified in court documents as K.G.M. and referred to as Kaley during the trial, told the court she began using YouTube at age six and later joined Instagram at nine despite parental restrictions.

She testified that her heavy use of social media affected her self-esteem and personal life.

She said her near-constant social media use “really affected my self-worth,” explaining that it caused her to abandon hobbies, struggle with friendships and constantly compare herself to others.

During the trial, the plaintiff’s lawyer, Mark Lanier, argued that platform features such as infinite scrolling, autoplay, notifications and like counts were designed to encourage addictive use among young people.

However, Meta and YouTube denied responsibility, insisting that the plaintiff’s mental health challenges were not linked to their platforms.

Meta’s legal team pointed to issues in her home life, while YouTube questioned the amount of time she actually spent on the platform.

The jury, however, rejected these arguments across all key questions.

TikTok and Snap were initially listed as defendants but settled the case before the trial began.

Two more similar trials are expected to take place in the same Los Angeles court, with outcomes that may influence whether tech companies push for settlements or adjust how their platforms operate.

Commenting on the development, industry analyst Jasmine Enberg said the financial penalty may not significantly impact the companies.

“The penalty amounts are “a slap on the wrist for companies like Meta and YouTube, which are two of the biggest ad sellers in the world,” said Jasmine Enberg of Scalable, who tracks the social media industry.

“But if these companies are forced to redesign their products, that poses an existential threat to their business models.”

In a related case, a New Mexico jury on Tuesday also found Meta liable for exposing children to risks, including online predators.

While the state had sought $2.2 billion in damages, the court awarded $375 million.