TORONTO — Five more Ontario school boards and two private schools have joined the multi-billion-dollar legal fight against social media giants Facebook, Instagram, TikTok and Snapchat, accusing their parent companies of leaving educators to manage the fallout from their allegedly addictive products.

They join some of Ontario’s largest school boards who filed suits in March alleging the platforms are negligently designed for compulsive use and have rewired the way children think, behave and learn.