In the DSM-5 the new Autism Spectrum Disorder will, for the most part focus on those with Aspergers' and high functioing autism. The vast majority of those with Autistic Disorder who are also intellectually disabled will be excluded. This is clear from the wording used in the proposed new Autism Spectrum Disorder and in the wording of the new Intellectual Developmental Disorder. That interpretation is also confirmed by the official rationale for the new ASD.
The new Autism Spectrum Disorder, as I have previously written, is misnamed. It would be much more accurately described as New Asperger's Spectrum Disorder. The new version, which will be rubber stamped, on final review by the APA DSM-5 work groups, will exclude persons with intellectual disability as the current DSM-IV Asperger's criteria does and will remove language delay and general communication impairment also making the ASD consistent with DSM-IV Asperger's criteria. In addition the DSM-5 ASD criteria make it clear that although the New ASD must be present from infancy or early childhood it may not be detected until later because of minimal social demands and support from parents or caregivers in early years. This consideration helps those on the milder end of the current autism spectrum.
As an example my son who is severely affected by his Autistic Disorder and profound developmental delays was diagnosed at age 2 several months after we had begun to seek medical attention for his lack of development. We knew nothing about autism but his lack of development was apparent and disconcerting. By contrast the media is full of stories of very high functioning persons, some of whom are now quite famous self appointed spokespersons on behalf of all persons with autism who were diagnosed as teens or adults. The "may not be detected until later" qualifier helps ensure that the New ASD captures those with Asperger's and High Functioning Autism.
I have previously noted that the criteria for the New ASD also excludes those with intellectual disabilities. It does so by:
1. Establishing 4 mandatory criteria each of which MUST be met before ASD will be diagnosed:
2. Excluding fulfillment of mandatory criterion A where that criterion can be accounted for by general developmental delay:
If a child has general deficits in communication it seems obvious that the general communication deficit will include social communication deficit. The DSM-5's new Intellectual Developmental Disorder confirms this assertion in mandatory Criterion B which specifically states that deficits in general mental ability impair functioning in various areas including communication and social participation:
The DSM-5's New Autism Spectrum Disorder rationale also confirms the exclusionary effect of the new Autism Spectrum Disorded Mandatory Criterion A by explaining why 3 domains will be collapsed into 2:
The explanation does continue on but the first example highlights why the reduction from 3 domains to 2 confirms that DSM-5 ASD mandatory Criterion A will exclude the intellectually disabled. As the DSM-5 description of Intellectual Developmental Disorder states the deficits in general mental abilities will impair functioning by limiting and restricting participation and performance in daily life activities such as communication and social participation. The rationale offered for the new ASD meanwhile states the obvious: deficits in communication and social behaviors are inseparable.
When a person suffers from general mental deficits sufficient to meet an Intellectual Developmental Disorder diagnosis he/she will suffer impairment in communication and social interaction. They are inseparable. In any instance where a persons meets the IDD criteria they will not meet criterion A of the New ASD because their persistent deficits in social communication and social interaction will be accounted for by general developmental delay.
The description of the DSM-5's new Autism Spectrum Disorder's mandatory Criterion A and the description of the new Intellectual Developmental Disorder combine to exclude from an Autism Spectrum Disorder diagnosis those who are intellectually disabled. That interpretation is confirmed both by common sense and by the DSM-5 rationale for the new ASD. 3 domains become 2. Deficits in communication and social behaviors are inseparable. Those with IDD will suffer deficits in communication and social behavior and will be accounted for by their IDD diagnosis thus excluding them from an ASD diagnosis.
In the brave new world of the DSM-5, as in the mainstream media, as in Hollywood, as in autism research generally, the Intellectually Disabled will be excluded from the autism spectrum.