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The Meta researcher’s tone was alarmed.

“oh my gosh yall IG is a drug,” the user experience specialist allegedly wrote to a colleague, referring to the social media platform Instagram.”We’re basically pushers… We are causing Reward Deficit Disorder bc people are binging on IG so much they can’t feel reward anymore.”

The researcher concluded that users’ addiction was “biological and psychological” and that company management was keen to exploit the dynamic. “The top down directives drive it all towards making sure people keep coming back for more,” the researcher added.

The conversation was included recently as part of a long-simmering lawsuit in a California-based federal court. Condensing complaints from hundreds of school districts and state attorneys general, including California’s, the suit alleges that social media companies knew about risks to children and teens but pushed ahead with marketing their products to them, putting profits above kids’ mental health. The suit seeks monetary damages and changes to companies’ business practices.