The decision has already been made by the American Psychiatric Association's DSM revision team to rename and revise the current Pervasive Development Disorders in the DSM-IV by combining them into one Autistic Disorder 299.0.
The DSM-5.org site presents a rationale for the changes including the observation that "A single spectrum disorder is a better reflection of the state of knowledge about pathology and clinical presentation; previously, the criteria were equivalent to trying to “cleave meatloaf at the joints”." I am not that big on meatloaf so they have lost me with that image.
- ... distinctions among disorders have been found to be inconsistent over time, variable across sites and often associated with severity, language level or intelligence rather than features of the disorder.
- Because autism is defined by a common set of behaviors, it is best represented as a single diagnostic category that is adapted to the individual’s clinical presentation by inclusion of clinical specifiers (e.g., severity, verbal abilities and others) and associated features (e.g., known genetic disorders, epilepsy, intellectual disability and others.)
As the father of a boy with Autistic Disorder with profound developmental delays, a boy who in ordinary language would be described as severely autistic and affected in every single aspect of his existence by a low functioning level I understand the severity aspect of the rationale for the New Autism Spectrum Disorder. I tire of listening to the barely autistic engineers, lawyers, writers, university students, successful business persons, Washington political circle navigators and IMFAR socialites who are interviewed daily by the main stream media and tell the world what it means to "be autistic".
Despite my previously expressed concerns (1, 2) about the New Autism Spectrum Disorder I can see the logic in one"spectrum" disorder as long as the spectrum is clearly differentiated, as the DSM-5 site suggests, based on severity. Unfortunately the DSM-5 people have committed to the New Autism Spectrum Disorder without having clear criteria for differentiating severity categories and criteria in the NASD, or at least without having communicated severity criteria to the public including "autism parents" like this Dad.
I don't know much about cleaving meatloaf at the joints but it seems to me that with the New Autism Spectrum Disorder the DSM-5 team has put the cart before the horse by committing to the creation of a single autism spectrum disorder, the New Autism Spectrum Disorder, which recognizes distinctions based on severity, without first clearly defining severity categories or criteria.
Until comprehensible severity categories and criteria are developed this father of a boy diagnosed with the current Autistic Disorder and assessed with profound developmental delays says NEIGH to the New Autism Spectrum Disorder.