LOS ANGELES, Feb 18 (Reuters) - Facebook founder and Meta Platforms CEO Mark Zuckerberg is set to be questioned for the first time in a U.S. court on Wednesday about Instagram's impact on the mental health of young users, as a landmark trial over youth social media addiction takes place.

Although Zuckerberg testified about this matter previously before Congress, the odds are much higher in a jury trial in Los Angeles, California. Meta could be forced to pay damages if it loses the case, and a ruling could undermine the long-standing legal efforts of Big Tech companies to defend themselves against claims of harming users.

This lawsuit and others like it are part of a global stand against social media platforms regarding children's mental health.

Australia and Spain have banned users under 16 from accessing social media platforms, and other countries are considering similar restrictions. In the United States, Florida has prohibited companies from allowing users under 14 to use their platforms. Technology industry groups are challenging this law in court.

The case involves a California woman who began using Meta's Instagram and Google's YouTube as a child. She alleges that the companies sought to profit by attracting children to their services despite knowing that social media could harm their mental health. She claims the apps exacerbated her depression and suicidal thoughts and is seeking to hold the companies accountable.

Meta and Google denied these claims, pointing to their efforts to add features that keep users safe. Meta frequently cited the National Academy of Sciences' conclusion that research does not show social media causes changes in children's mental health.