Visiting social media can be a daily compulsion that may feel addictive, in a sense. Now California jurors say that two tech giants, Meta (owner of Facebook and Instagram) and Google (YouTube's parent), must pay $6 million total to compensate a young woman who claimed in a lawsuit that the firms' design features are addictive and caused her anxiety, depression, body shame and suicidal thoughts. (TikTok and Snap settled before the trial.) A week earlier, New Mexico jurors found Meta liable for failing to protect young people from online dangers, including sexually explicit content, solicitation and human trafficking. The company is appealing the verdict and accompanying $375-million penalty.

This month's landmark decisions, based on a novel legal theory that social media sites or apps can cause personal injury, could open the owners to more suits over users' well-being. More than 3,000 other similar cases against Meta, YouTube, Snapchat and TikTok are pending in California, and the first federal trial is set for June in San Francisco. The internet giants may feel pressure to adjust their products to avoid further penalties.

The cases filed by parents, school districts and state attorneys general seek to prove that harm flows from how social platforms are designed and run, not from their content – which the firms aren't legally responsible for. Social media operators are accused of creating products as addictive as cigarettes or digital casinos. Critics point to infinite scroll, which entices people with seemingly endless content, algorithmic recommendations and autoplay videos that start without a click.

In Washington, Sen. Marsha Blackburm, R-Tenn., welcomed last week's Los Angeles verdict by saying: "Now that Big Tech has been found liable for the harms they have pushed on our kids, it's time for Congress to enshrine protections for American families into law by passing the Kids Online Safety Act." A Democratic colleague, Sen. Edward Markey, agreed and said: "I commend the courageous kids and families who are pursuing these cases and fighting to hold Big Tech accountable. . . . Congress must do its part to impose real guardrails on these platforms."

California woman who sued says: "I wanted to be on [Instagram] all the time. If I wasn't on it, I felt like I was going to miss out on something." – "Kaley M.," 20, of Chico

Meta says: "Teen mental health is profoundly complex and cannot be linked to a single app. We will continue to defend ourselves vigorously, and we remain confident in our record of protecting teens online."

Winning lawyers say: "For years, social media companies have profited from targeting children while concealing their addictive and dangerous design features. . . . Accountability has arrived."