Feb 11 (Reuters) - Instagram's leader is set to face

questions in court for the first time on Wednesday about whether

the Meta-owned app's design is fueling a youth mental

health crisis.

Adam Mosseri, the head of Instagram, will ​testify in Los

Angeles as part of a ‌trial on what plaintiffs call "social media

addiction" in children and young adults. Meta CEO Mark

Zuckerberg is also ⁠expected to testify in the coming weeks.

The case involves a 20-year-old woman ⁠who said she became

addicted to Instagram at a young ‌age because of ‌its

attention-grabbing design, according to court filings.

The outcome of her case will influence how social media

companies ​respond to hundreds of similar lawsuits in ‌the U.S.

"We strongly disagree with these allegations and are

confident the evidence will show our longstanding commitment to

supporting young people," a ​Meta spokesperson said in a

statement ​ahead of ‌Mosseri's testimony.

The California woman said in a deposition that Instagram's

"endless" scroll feature kept her on the app and contributed to

her anxiety, according ⁠to court filings.

Endless scroll is a design feature where content loads

continuously ⁠as the user moves down the page. The American

Academy of Pediatrics said in January that the feature may make

it harder for kids to "disengage from digital devices."

Mosseri is expected to be questioned on internal company

documents.

The plaintiff's counsel ⁠said the ‌records show the company

was aware of harms to children ‌from using Instagram. The

attorneys pointed to a recent Meta study they said ⁠showed that

teens facing other difficulties in their lives were the most

likely to become addicted and that parents had no meaningful

control.

Meta's lawyer said in court that the company's internal

discussions were for the purpose of addressing problems and

adding features to give users more control.

Access to social media for children has become an issue

globally, with Australia ​in December becoming the first nation

to prohibit use of the platforms for children younger than 16.

Spain, Greece, Britain and France are among the many countries

considering ​similar action.