Snapchat’s parent Snap has settled a social media addiction lawsuit just days before the landmark case was due to go to trial in Los Angeles.

Terms of the deal were not announced as it was revealed by lawyers at a California Superior Court hearing, after which Snap told the BBC the parties were “pleased to have been able to resolve this matter in an amicable manner”.

Other defendants in the case include Instagram parent Meta, ByteDance’s TikTok and Alphabet’s YouTube, none of which have settled.

The plaintiff, a 19-year old woman identified by the initials K.G.M., alleged that the algorithmic design of the platforms left her addicted and affected her mental health.

In the absence of a settlement with the other parties, the trial is scheduled to go forward against the remaining three defendants, with jury selection due to begin on 27 January.

Meta boss Mark Zuckerberg is expected to testify, and until Tuesday’s settlement, Snap CEO Evan Spiegel was also set to take the stand.

Meta, TikTok and Alphabet did not respond to BBC inquiries seeking reaction to the settlement.

Snap is still a defendant in other social media addiction cases that have been consolidated in the court.

The closely watched cases could challenge a legal theory that social media companies have used to shield themselves.

They have long argued that Section 230 of the Communications Decency Act of 1996 protects them from liability for what third parties post on their platforms.

But plaintiffs argue that the platforms are designed in a way that leaves users addicted through choices that affect their algorithms and notifications.

The social media companies have said the plaintiffs’ evidence falls short of proving that they are responsible for alleged harms such as depression and eating disorders.