One of the reasons Autism, ADHD, etc are increasing is they are over-diagnosed. Back in the day, a kid wasn't "Hyperactive" he was a normal 7 year old that needed to get out in the neighborhood and wear himself out playing with all the other 7 year olds. Nowdays, Mommy wants some of his speed prescription so she hauls him down to the Docs who prescribe Ritalin or whatever and send him on his way. Sure, there are some hyper kids, but not the millions being medicated.
Autism is especially over-diagnosed. My friend has an autistic 40 year old. He will never function above the level of a 3 year old. He spends his days sitting staring at things and wagging his head back and forth while loudly sucking air in and out between his teeth. He screams at all hours of the day and night, and will not stop. He has to have his grooming done for him, and is very upset when his routine is disrupted. His parents are Saints, anybody will tell you he should have been institutionalized years ago. He is truly Autistic, no idea why. Nowdays, little Johnny daydreams a bit in class and the next thing ya know he's slapped with the Autistic label. When their son was small, it took dozens of specialists and hospitals before they even got the Autism diagnosis, and that was mainly because his Father read up on the literature and found a Doc who specialized in it. When he was of school age, he was sent to special ed classes, there were a total of 3 Autism kids in the entire state at that time. Now we have thousands.