Children and adolescents are especially susceptible to harm because their brains are not fully developed, the lawsuit said.

"Youth are now addicted to defendants’ platforms in droves,” according to the 311-page filing in Superior Court in California, where the companies are headquartered.

The country’s largest school district, with about 1 million students, has had to respond to disruptions in and out of the classroom, provide counseling for anxiety and depression, and develop curricula about the effects of social media and how to stay safe online, according to the filing. The city spends more than $100 million on youth mental health programs and services each year, Mayor Eric Adams’ office said.