what facts do you have in supporting your statements? no "actual" studies proves your statements.

It may or may not have been there in the past but since medical field are not as advance as now on some of this syndrome may have just been seen as a problematic misbehaved children.
with current medical field advancement a lot of disease or syndrome are able to be diagnosed better and earlier so intervention can begin earlier.

remember when people used to see bomoh when people have abnormal growth/tumour/cancer on their body and bomoh will say kena buatan orang.
now with increased public awareness and medical detection it can be diagnosed earlier and treated which higher chance of recovering compared to last time.

same can be said with autism.15 years ago ive never heard of the word spoken by anyone. now everyone now what autism is.