They built social media on the back of attention-seeking and egotism. That's the currency—ego—and the stuff that's transmitted is high emotional content, high anger, sometimes humor.
Now we have a three-way storm: the narcissists and the sadists rule, optimized by the social media algorithms. Even more importantly, the only thing that matters is capturing someone's attention now. What that seems to mean is that we've created an environment where the mindset of an immature narcissist is reinforced constantly, algorithmically, with the AI systems. It's kind of like if you're in a classroom and you have to listen to the noisiest and most obnoxious person in the room all the time.
It is remarkably addictive. I've also found there's been a shift in my reading habits. Partly because it's more effortful to read a classic, especially if I'm tired, it's easy to default to the fire hose of at least pseudo-information that X provides.
One of the problems with social media pathology might merely be that it's free. People's attention is so valuable that if it's distributed for free, the psychopaths are going to take glorious advantage of that in a major way. That's another problem with the way these games are set up now.