Analysis credits diagnostic change with increased cases of autism

“Autism Awareness” puzzle-piece ribbon magnet on a car
Photo by Cynthia Parkhill

On Disability Scoop, Shaun Heasley summarizes a new study suggesting that changes to autism diagnostic criteria may be more responsible than anything else for rising prevalence rates.

Researchers applied current diagnostic criteria to data from a 1980s study on autism prevalence.

I appreciate this study bcause it corroborates my argument: that improved detection is responsible for an increased number of cases of autism. I disagree with highly-politicized reactions to autism prevalence rates.

From the June 29 summary on Disability Scoop:

“The original study, published in 1989, looked at hundreds of Utah residents ages 3 to 25 who were suspected to have autism. Clinicians used DSM-III criteria to assess individuals as ‘diagnosed autistic’ or ‘diagnosed not autistic’ and ultimately found an autism prevalence rate of 4 in 10,000 in Utah at that time.

“But when a research team from the University of Utah applied current diagnostic criteria from the DSM-IV-TR to records from participants in the two-decades-old study, they found that most who were deemed to be autism-free at that time would receive the label today.”

Speaking for myself, it was immensely reassuring to receive diagnosis in adulthood. For people like me, whose challenges went undetected while we were growing up, this study is additional good news. From Disability Scoop:

“The analysis found that 59 percent of those who were ‘diagnosed not autistic’ in the 1980s would qualify as having autism today, while an an additional 38 percent of people showed some characteristics of autism. 

“Meanwhile, those who were found to have autism in the 1980s study continued to qualify for the diagnosis using the current criteria, the study found. 

“‘The results of this study demonstrate a significant effect on ASD case status attributable to changing ASD criteria, particularly with regard to individuals with intellectual impairment,” the researchers said. “An important caveat, however, is that we were unable to determine whether it was the broadening of the criteria themselves, or the interpretation of the criteria, which lead to this effect.’”