A new study from Penn State has revealed that almost all the increase of Autism cases in the United States between 2000 and 2010 are results of reclassification. To be more precise, the primary reason behind the increase in autism in the country is reclassification of children demonstrating intellectual disabilities as autistic.
Researchers have reported that even after several decades of autism’s introduction as diagnosis professionals are taking part in diagnostic substitutions pretty regularly. They are moving people belonging to various diagnostic categories such as mental retardation, language impairment etc. to autism.
For instance, during a recent study, 489 children living in Utah since 1980 got reexamined by researchers representing ULCA. According to the initial results reported by a 1990 study, 108 kids in the group belonged to the “challenged” category, which in today’s jargon means “intellectually disabled”, but not autistic.
After returning with the aim of applying present day diagnostic standards for autism for the 108 children categorized as “challenged”, researchers found that 64 of them could be tagged as autistic other than being classified as kids with intellectual disability.
There was another study conducted by a team led by Dorothy Bishop that re-evaluated adults who were found to be suffering from developmental language disorder as children, but was not categorized as autistics.
Bishop and the research team under her used a couple of diagnostic tools for re-evaluating these adults. They found that although they were not diagnosed with the condition, a fifth of these individuals met the standards set for autism spectrum.
The latest study carried out by Penn researchers was led by Santosh Girirajan. During the study, Girirajan and his team looked at and analyzed data concerning special education enrollment of 6.2 million kids.
While the number remained almost stable for 11 years, there were slight shifts in diagnostic categories. An increase in the number of autism diagnoses was observed, while the number of students classified as intellectually disable decreased.
Another factor influencing this change is age of the child. The shift was more common in older groups than younger groups. The shift resulted in 59% increase in autism cases among eight year olds. In 15-year-old kids, the increase was by almost 97%.