There is more evidence this month demonstrating that we are not, in fact, presently suffering through an age of increased incidence of autism, but rather as the definition of autism is refined, we discover individuals who were previously misdiagnosed. A University of Oxford study has followed up with a group of 38 adults who were originally involved in a series of studies on developmental language disorders in the late 80s and 90s. Those who manifest symptoms of the disorders have difficulty with spoken language, a trait also seen in autism. All of the subjects had attended specialized schools and were previously not diagnosed with autism.
Using today’s criteria, the researchers found nearly a quarter of the participants to have an autistic disorder rather than one based on spoken language. “Our study shows pretty direct evidence to support the theory that changes in diagnosis may contribute towards the rise in autism,” says Dorothy Bishop, the lead on the new study. “These were children that people were saying were not autistic in the 1980s, but when we talk to their parents now about what they were like as children, it’s clear that they would be classified as autistic now.”