Meta has reached a settlement with a US school district which had sued the Instagram-owner over the costs of fighting a mental health crisis allegedly caused by the company's social media platforms.

Breathitt School District, located in the US state of Kentucky, had been poised to file the first case seeking to hold social media companies liable for those costs.

The school district settled the same case last week with three other defendants: TikTok, Snap Inc, and Google's YouTube.

"We've resolved this case amicably," a Meta spokesperson said on Thursday of the agreement, which allows it to avoid mounting a defence at this trial, although similar cases remain set for trial in the near future.

Breathitt County School District's case was chosen as a test case for more than 1,000 US school districts that have pursued claims against social media companies.

The school district alleged the companies deliberately designed their platforms to be addictive, resulting in harms ranging from anxiety and depression to self-harm.

It was seeking $60m (£44.7m) in damages to address the impacts of social media on students, as well as an abatement program.

The district also wanted the companies to change the alleged addictive nature of their platforms.

The trial was slated to begin in mid June in federal court in Oakland, California as part of a multi-district litigation.

A bellwether trial for cases brought against Meta by US states is set to proceed in the same court starting in August.

Terms of Thursday's settlement with Meta were not disclosed.

"Our focus remains on pursuing justice for the remaining 1,200 school districts that have filed cases," said plaintiffs' attorneys Lexi Hazam, Previn Warren, Chris Seeger and Ronald Johnson in a statement.

Earlier this year, Meta and YouTube lost a high-profile case brought in Los Angeles by a woman who alleged the companies were responsible for her childhood addiction to social media.

The 20-year-old woman, known as Kaley, was awarded $6m (£4.5m) in damages after jurors agreed with her claim that the companies intentionally built addictive social media platforms that harmed her mental health.

At the time, Meta and Google said they intended to appeal.

Snap and TikTok settled that case just prior to that trial, which was a bellwether case for similar lawsuits brought in state court.

On Thursday, a Meta spokesperson said the company remained "focused on our longstanding work to build protections like Teen Accounts that help teens stay safe online, while giving parents simple controls to support their families".

Instagram Teen Accounts was launched two years ago as a tool designed to protect teenagers from harmful content.

But some researchers say the tool fails to stop young users from seeing suicide and self-harm posts.

"When you have products designed to maximise capture of your attention, some people are going to have a harmful relationship to it," said Arturo Béjar, a Meta whistleblower who has testified against the company.

Earlier this week, the Tech Transparency Project, an advocacy group, said Meta has been paying Instagram influencers to positively shape the narrative around its Instagram Teen Accounts.