Dr. Frances, a psychiatrist, led the task force that created the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders.

You know, what happened was, in 1994, we added a condition that was called Asperger’s disorder that was a very mild form of some of the same symptoms that occur in classic autism. Classic autism is absolutely unmistakable. The onset is before the age of 3. Severity and disabilities are tragic and lifelong, and you cannot mistake classic autism for anything else.

Asperger’s is a very mild version of classic autism and therefore much more common and much more easily mistaken for other mental disorders or for normal eccentricity and social withdrawal. So the 60-fold increase was largely started by the change in definition in DSM-IV, and then it was promoted by several factors. First and foremost, originally, it was the fact that educational services were geared to getting the diagnosis. And anytime there’s a benefit related to a psychiatric diagnosis, it - rates jump enormously.

Secondly, the internet spread the idea of autism like wildfire. And many people incorrectly self-diagnosed themselves with autism. In some places, it became almost a badge of brilliance. And so the differences in the definition and differences in the application of the definition and the fact that educational benefits have been associated with it - that’s what caused the 60-fold increase - not vaccines. We know from very conclusive studies that vaccines do not cause autism.