I have commented for the past 2 1/2 years on the DSM5's targeted exclusion of the intellectually disabled. The new definition excludes persons with profound intellectual disability from an autism diagnosis even if they display ALL of the diagnostic criteria. This exclusion is derived from the convenience of researchers and clinicians who find the challenge of working with severely autistic, profoundly intellectually disabled persons too overwhelming. Dr. Lord herself pointed out in Dr. Catherine Lord of the DSM5 committee that has crafted the New Autism Spectrum Disorder has also noted the tendency of autism research to exclude those with multiple disabilities and moderate and severe intellectual disability in Social Policy Report, Autism Spectrum Disorders Diagnosis, Prevalence, and Services for Children and Families : ""However, research in ASD has tended to use overwhelmingly White, middle to upper middle class samples, and has often excluded children with multiple disabilities and/or severe to profound intellectual disabilities". [underlining added - HLD]
Parents of children with severe autism and intellectual disabilities can not simply abandon our children. Unlike parents, autism researchers and DSM5 autism committee members do not have to find ways to work with the most challenged autism cases. They simply exclude them by redefining them out of the spectrum. They do so by ignoring the evidence of those diagnosed with autism and ID by existing criteria.
The express exclusion, "not accounted for by general developmental delays" occurs in the introductory paragraph to mandatory criterion A of the DSM5 ASD definition:
"Autism Spectrum Disorder
Must meet criteria A, B, C, and D:
A. Persistent deficits in social communication and social interaction across contexts, not accounted for by general developmental delays, and manifest by all 3 of the following:"
Lynn Waterhouse in her newly released book "Rethinking Autism" Variation and Complexity, pages 382-385, references this express exclusion and argues that the exclusion of those with intellectual disability is NOT evidence based. She points out that the exclusion is based on a faulty, non evidence based assumption that a person's intellectual or cognitive disability causes the social communication deficits. Waterhouse argues that the exclusion of the intellectually disabled IGNORES evidence of published, credible, studies indicating that 55-70% of those diagnosed with autism by prior criteria experienced intellectual disability based developmental delays. The exclusion also ignores genetic, chromosomal and neuroscience studies showing substantial overlap between cognitive disability and social communication deficits.
Dr. Lord confessed in the NYT Amy Harmon interview that the DSM5 team targeted intellectually disabled for exclusion from the new Autism Spectrum Disorder. That targeted exclusion of the intellectually disabled is not evidence based. It is not helpful to understanding autism disorders generally and will cause harm to the most severely affected by autism, the ones who are, apparently, too much of a challenge for Lord and the DSM5 Autism Do-Over team. The exclusion of the intellectually disabled from the new autism disorder while not evidence based serves the interests of researchers, clinicians and services providers who lack the good conscience and the intestinal fortitude to work with the most severely affected by autism disorders: those with general developmental delays, those with intellectual disability.
I don't know if the DSM5 Autism team has a motto. An accurate, honest one might be:
"DSM5, simplifying autism complexity by ignoring the evidence; helping those with autism disorders, except those who are too challenging and inconvenient."