Lawyers representing 29 US states on Tuesday accused Meta of hiding internal research that allegedly found Instagram could be addictive for teenagers, The Guardian reported.The allegations were made as a major legal battle against Meta began in a federal court in Oakland, California. The trial is expected to continue for six to eight weeks.According to the lawsuit, Meta of deliberately designing Instagram and Facebook features to keep young users engaged, despite knowing that some of those features could harm their mental health.Megan O’Neill, a deputy attorney general for California, told the jury that Meta failed to act despite being aware of the risks.“I heard from many of you at jury selection that the health and wellbeing of kids is a shared responsibility,” O’Neill said. “Meta didn’t do its share.”O’Neill said lawyers would present internal documents and testimony obtained during investigations into Meta.She referred to one document that stated, “the young ones are the best ones”. Another allegedly stated: “Teens are hooked despite how it makes them feel. Instagram is addictive.”“They knew,” O’Neill said. “Time and again, profits won.”The 233-page lawsuit, filed in October 2023, also alleges that Meta collected data from children under 13 without parental permission, violating federal and state laws.The states claim Meta “refuses to abandon its use of known harmful features” and has sought to “maximize its financial gains”.The states have said Meta could face damages of up to $200 billion if found liable. They are also seeking changes to Meta's products to make them safer for children.Meta has denied the allegations. Its lawyer, Paul Schmidt, argued that the internal documents and emails presented by the states were selectively quoted and taken out of context.