Alphabet’s Google and Meta were found liable ​on Wednesday for designing platforms that are dangerous for teens, in a landmark verdict that could force tech firms to rethink how they defend themselves against ‌safety claims.

The verdict could mark a turning point in the global backlash against their platforms’ perceived mental health harms to kids and teens, more than two decades after the emergence of social media.

Punitive damages for the companies will be decided next. The jury may consider whether Google or Meta’s products caused the plaintiff physical harm or whether the companies disregarded the health of other users, Judge Carolyn Kuhl said in court.

The case involves a ​20-year-old woman, a minor when the case began who is known in court by her first name Kaley. She said she became addicted to Google’s YouTube and Meta’s Instagram at ​a young age because of their attention-grabbing design. The jury found Google and Meta were negligent in the design of both apps and ⁠failed to warn about their dangers.

“Today’s verdict is a referendum — from a jury, to an entire industry — that accountability has arrived,” the plaintiff’s lead counsel said in a statement.

Shares of Meta were ​up nearly 1% and Alphabet shares were slightly lower, little changed after the verdict.