One of the big topics of discussion in the past few years was the roll out of the DSM-5. The new criteria for what defines autism. One could find those saying “this is designed to undiagnose autistics with intellectual disability” as well as “this is designed to undiagnose autistics without intellectual disability” together with the multiple comments that “this is designed to obfuscate the “epidemic” of autism”.
A recent paper discusses this: Potential Impact of DSM-5 Criteria on Autism Spectrum Disorder Prevalence Estimates. The study looks at the CDC’s ADDM network–the same basis for the CDC autism prevalence estimates that come out every two years.
I haven’t read the full paper yet, but here’s the abstract:
IMPORTANCE The DSM-5 contains revised diagnostic criteria for autism spectrum disorder (ASD) from the DSM-IV-TR. Potential impacts of the new criteria on ASD prevalence are unclear.
OBJECTIVE To assess potential effects of the DSM-5 ASD criteria on ASD prevalence estimation by retrospectively applying the new criteria to population-based surveillance data collected for previous ASD prevalence estimation.
DESIGN, SETTING, AND PARTICIPANTS Cross-sectional, population-based ASD surveillance based on clinician review of coded behaviors documented in children’s medical and educational evaluations from 14 geographically defined areas in the United States participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network in 2006 and 2008. This study included 8-year-old children living in ADDM Network study areas in 2006 or 2008, including 644 883 children under surveillance, of whom 6577 met surveillance ASD case status based on the DSM-IV-TR.
MAIN OUTCOMES AND MEASURES Proportion of children meeting ADDM Network ASD criteria based on the DSM-IV-TR who also met DSM-5 criteria; overall prevalence of ASD using DSM-5 criteria.
RESULTS Among the 6577 children classified by the ADDM Network as having ASD based on the DSM-IV-TR, 5339 (81.2%) met DSM-5 ASD criteria. This percentage was similar for boys and girls but higher for those with than without intellectual disability (86.6% and 72.5%, respectively; P <.001). A total of 304 children met DSM-5 ASD criteria but not current ADDM Network ASD case status. Based on these findings, ASD prevalence per 1000 for 2008 would have been 10.0 (95% CI, 9.6-10.3) using DSM-5 criteria compared with the reported prevalence based on DSM-IV-TR criteria of 11.3 (95% CI, 11.0-11.7).
CONCLUSIONS AND RELEVANCE Autism spectrum disorder prevalence estimates will likely be lower under DSM-5 than under DSM-IV-TR diagnostic criteria, although this effect could be tempered by future adaptation of diagnostic practices and documentation of behaviors to fit the new criteria.
Based on this, about 20% of those who would receive an ASD diagnosis under DSM-IV will not get one under DSM-5. The decrease was seen in both autistics with and without intellectual disability–with a larger decrease for those without ID. At the same time, some kids who were not previously identified as autistic would be under DSM-5.
By Matt Carey