I was in middle school when the iPhone first became popular among teens. Within a couple of months, everything changed. Kids talked a lot less on the bus, at lunch, etc. If you didn't have an iPhone, your friends probably did, so same issue. It felt a whole lot worse and stayed that way. I ended up becoming closer with my few friends who didn't have phones and further from my old best friends, just because of who was more willing to hang out together.
Apps on your tiny computer are engineered to get you hooked. The time that you spend on it is time that you cannot spend making and cultivating face-to-face friendships.
As far as I can tell, friendships are necessary for mental health. So those apps have a negative effect on your mental health.
In principle, they could also have a positive effect that counterbalances the negative. But in my personal experience, that's dubious.
Right, you need a mechanism. (Ice cream makes you fat, fat people can't swim, ergo drownings). Haight clearly outlines the mechanisms by which social media and smartphones have detrimental effects on mental health, see: https://www.youtube.com/watch?v=-l2TdinWoM8
And if you swim enough, you can't get fat no matter how much ice cream you eat. Ever seen the diet Phelps was on? Guy ate like crap, has over 20 gold medals to his name.
