To what degree should companies be responsible for goods which, without structured or disciplined use leads to harm, especially when the good in question has an apparently reasonable use case?
Drugs. The term you are looking for is drug, because numerous studies have shown the effect on brain chemistry[2] and behavior[1] from social media addiction could be as bad as hard drugs.
[1] https://www.addictioncenter.com/news/2019/09/excessive-socia...
[2] https://neurogrow.com/what-social-media-does-to-your-brain/