A landmark social media addiction trial in which top tech executives are expected to testify begins on Tuesday in California.
The plaintiff, a 19-year-old woman identified by the initials KGM, alleges the design of the platforms' algorithms left her addicted to social media and negatively affected her mental health.
The defendants include Meta - which owns Instagram and Facebook - TikTok's owner ByteDance and YouTube parent Google. Snapchat settled with the plaintiff last week.
The closely-watched case at Los Angeles Superior Court is the first in a wave of such lawsuits, which could challenge a legal theory used by tech firms to shield themselves from culpability in the US.
The named social media companies have said the plaintiff's evidence falls short of proving they are responsible for alleged harms such as depression and eating disorders.
