Personally, it hasn't changed but a climate has emerged from that environment that has fostered "different variables" that has exacerbated childhood conditions emerging and manifested as non chronic diseases.
My sense is that today the food element has been so butchered in the fast food comples (denatured, not enough real ingredients, fillers in food lacking in vitams/nutrients) children beign indoctrinated by being told what and when to thinks vs how to think (assess, analyze, weigh sides of a story/argument), the advents of what is called "social media" "influencers" and the politicization of basic issue of history turned upside down that the young face the confusion of their parents and as such suffer the consequences in manby way. ADHD has been so documented and an 1000% increase over the past 2 decades Something is definitely taking place on a grand scale!
I cannot imagine (though it happens) that children from the "majority", having most of the benefits and priviledges of what the society has to offer, going out and getting an AR-15 and shooting up a school? For what? Many times the children are elementary school, unable to fend for themselves and are shoot like wild pigs at a hog hunt. Why? There is something rotten in USA