As a person who actually deals with autism in the professional world, I say be very careful what you believe. We now have a whole generation of kids who are getting whooping cough because someone didn't vaccinate his/her kid. Truth is, there are a lot of neuroscientists and cognitive specialists trying to figure out what causes autism spectrum disorders. While we've come a long way from blaming a "cold mother" for ASD, we still don't know the answers. ASD has always been around, as have depression, PTSD, and ADHD. Back in the day, we just threw those people out of school, families kept them at home, or they ended up in state institutions. And we didn't talk about it, either. I am not advocating a return to that, just pointing out that numbers are skewed when looking at prevalence of mental health or brain disorders. We simply didn't acknowledge them, even when I was a kid in the 50s and 60s.