Lack of defensive measures in the young brain means use of social media and similar addictive software causes harm to children. It seems obvious, and research is now beginning to explain it better.

…screen use was linked to worse mental health and suicidal behavior. Teens are susceptible to the addictive qualities of social media because their brains are not fully developed, according to Joel Frederickson, a psychology professor at Bethel University. Features of social media apps, such as follows, likes and comments keep users coming back for more. This reward system makes the brain release a lot of dopamine, similar to how substance addiction works.

Notably the externalized “reward system” undermines the development of self worth and concepts of belonging. Thus the child instead has feelings of low worth and isolation, grasping for more and more “reward” from the external source, which can never deliver real value.