This is the first time I heard of Type 1, 2, and 3 Autism. I was under the impression that DSM-V eliminated subtypes from the diagnostic, and favored a multi-dimensional under a single category (maybe it is still an ICD-11 thing, which I think has 8 subcategories).
Wikipedia has this to say:
> Disagreements persist about what should be included as part of the diagnosis, whether there are meaningful subtypes or stages of autism.
And cites a paper [1] claiming:
> The elimination of subcategories was controversial for various reasons, including concerns over the removal of an important part of an individual’s identity and community, specifically related to Asperger’s disorder, as well as concerns over losing services due to an individual no longer meeting more stringent diagnostic criteria. However, the evidence for the existence of subcategories within ASD has continued to be very weak (Miller and Ozonoff 1997, 2000). Furthermore, the shift from multiple subcategories to a single dimension resulted in improved diagnostic specificity and good diagnostic sensitivity, with over 90% of children with PDDs meeting DSM-5 ASD criteria (Huerta et al. 2012; Mandy et al. 2012), and with the remainder likely captured by the new social communication disorder diagnosis.
It looks to me that if they would have kept multiple categories, that would have been a political decision (in particular, identity politics for thous which identify as Asperger’s). It seems like the current single category / multiple dimensions has proven it self to be a much better approach for diagnostic. That is evidence suggest this is a successful change, with both autism advocates and psychiatrists preferring the current single category approach.
I actually went ahead and read both the ICD-11[1] and the DSM-5[2] criterion for Autism Spectrum Disorder. When you referred to Type 1, 2 or 3 Autism what I think you were talking about is actually severity levels in criterion A (social communication and social interaction across multiple contexts) and criterion B (restricted, repetitive patterns of behavior, interests, or activities) of DSM-5. Level 1 requires less accommodations and level 3 requires very substantial support. Note that even level 1 severity requires support and states that without support an autistic person will have impaired social interactions.
These severity levels do not specify intellectual impairment, only social communication impairment and restrictive and repetitive behavior. Intellectual impairment is specified as a boolean with or without. So basically—as I understand it—what was previously described as Asperger’s is basically Autism spectrum Disorder with this boolean set to false.
I actually went ahead and did some further reading and it turns out that people (both psychiatrists, researchers, and autism advocates) are very happy with this arrangement. Intellectual impairment does not correlate (or correlates rather barely) with other required specifications of the disorder (including impaired social communication) and the accommodations required are vastly different.
ICD-11 has 8 subcategories of Autism Spectrum Disorder, and what was previously called Asperger’s is probably 6A02.0 - without disorder of intellectual development and with mild or not impairment of functional language. (pp. 36)
Note that psychiatrists and researchers alike are no fans of the ICD-11 approach, claiming things like:
> As ICD-11 defines ASD in a broad constellation of symptoms or behaviors that can hardly be differentiated from other mental disorders and autism-like traits, the risk of false positive ASD diagnoses increases significantly. This will lead to further limitation of access to ASD-specific services for individuals with a true positive diagnosis of ASD and likewise disadvantages individuals with a false positive diagnosis of ASD due to delays in access to or even missing out on disorder-specific care (e.g., dialectical behavior therapy for borderline personality disorder). Further, since ICD-11 draws particular attention to high-functioning (adult) individuals with ASD, there is concern that “prototypical” as well as low-functioning cases increasingly become neglected in research and clinical practice. [3]
Wikipedia has this to say:
> Disagreements persist about what should be included as part of the diagnosis, whether there are meaningful subtypes or stages of autism.
And cites a paper [1] claiming:
> The elimination of subcategories was controversial for various reasons, including concerns over the removal of an important part of an individual’s identity and community, specifically related to Asperger’s disorder, as well as concerns over losing services due to an individual no longer meeting more stringent diagnostic criteria. However, the evidence for the existence of subcategories within ASD has continued to be very weak (Miller and Ozonoff 1997, 2000). Furthermore, the shift from multiple subcategories to a single dimension resulted in improved diagnostic specificity and good diagnostic sensitivity, with over 90% of children with PDDs meeting DSM-5 ASD criteria (Huerta et al. 2012; Mandy et al. 2012), and with the remainder likely captured by the new social communication disorder diagnosis.
It looks to me that if they would have kept multiple categories, that would have been a political decision (in particular, identity politics for thous which identify as Asperger’s). It seems like the current single category / multiple dimensions has proven it self to be a much better approach for diagnostic. That is evidence suggest this is a successful change, with both autism advocates and psychiatrists preferring the current single category approach.
1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8531066/