Trends in autism spectrum disorder diagnoses: 1994-2007.
School teams swapped 'PDD-NOS' for 'ASD' and 'Asperger' long before the manuals did, so dates matter when you read old reports.
01Research in Context
What this study did
Lancioni et al. (2009) looked at school records from 1994 to 2007. They counted how often teams wrote 'ASD,' 'Asperger,' or 'PDD-NOS.'
They also noted the child's race, where the family lived, and who gave the label.
What they found
The labels 'ASD' and 'Asperger' grew fast. The label 'PDD-NOS' dropped.
White children, suburban schools, and psychologist-led teams used the new terms most.
How this fits with other research
Hastings et al. (2001) saw the same climb in Iceland a few years earlier. Their numbers show the trend started before US schools caught on.
Baron-Cohen et al. (2005) built a stricter adult Asperger test. Their tool aimed to shrink over-diagnosis, yet schools kept handing out the Asperger label more often.
Silleresi et al. (2020) later showed that kids sort into clear language-cognitive groups. Their work hints that the old label jump may have hidden real skill differences.
Why it matters
When you read an old file that says 'PDD-NOS,' know the same child might today be called 'ASD.' Check the evaluation date before you compare data across years. If you write a report now, pick the label that matches current manual terms and note the change so future teams are not confused.
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02At a glance
03Original abstract
We analyzed predictors of parent-reported initial diagnosis (autistic disorder [AD], pervasive developmental disorder-not otherwise specified [PDD-NOS], pervasive developmental disorder ['PDD'] and autism spectrum disorder ['ASD'], and Asperger syndrome [AS]), among 6,176 individuals with autism spectrum disorders diagnosed from 1994 through 2007. Overall, distribution of diagnoses was influenced by a secular time trend factor; other significant factors included ethnicity, white race, geographic location, urbanicity, and initial evaluator. Since 2001, most initial diagnoses of AD and AS have remained steady while 'PDD' and PDD-NOS have decreased. 'ASD' diagnoses have increased, especially among school-based teams; AS diagnoses also increased uniquely among these evaluators. Findings from this study suggest that current diagnostic guidelines may not be meeting all community evaluator needs.
Journal of autism and developmental disorders, 2009 · doi:10.1007/s10803-009-0723-6