> Because I don't buy this narrative from the article or in medical research that there are two kinds of autism.
I'd like to preface this by saying I don't feel strongly about the naming issue in either direction.
Initially I figured the authors were using the word "Autism" as used in DSM-5, where it's a blanket term for a range of conditions. But, their repeated assertion of "two types" of autism doesn't line up with that theory: DSM-5 defines three levels, not two.
They definitely aren't using the DSM-IV definition of Autism (the stricter definition that you prefer), and they also aren't following the taxonomy laid out in DSM-5. Where did their definition of Autism come from?
Was it implied that their two-level model was derived from the results of their tests? If so, I missed that part. They mention a correlation between brain overgrowth and severity of symptoms, but they don't mention a clear separation in the test data that would justify classification into two distinct groups.
I understand that DSM isn't gospel, but if they're going to make up their own taxonomy, they should provide some rationale for it.
Hardly, the study it self refers to which subtypes they are talking about in the conclusion:
> the biological bases of two subtypes of ASD social and brain development—profound autism and mild autism.
The Methodology section actually specifies they are using DSM-V (sic) and “Mann–Whitney U to test ASD clinical subtype differences in symptom severity” as well as that they test for IQ. They also specify which instruments they used to test symptom severity, neither of which actually measures subtypes of autism.
This is highly confusing as DSM-5 does not have any subtypes of autism. It has 3 severity levels for two of the symptoms criteria which is used to specify the accommodation needs. Those symptoms criteria is social communication and repetitive and fixated behavior. Intellectual ability is not on this severity level, instead psychiatrists are instructed to specify whether or not autism is accompanied with intellectual impairment. Further if you look at their table 1[1] you can see what they mean by the two subtypes, which is basically, low IQ vs. normal IQ.
This is actually much closer to ICD-11 where one of the 8 subtype of autism is 6A02.0 - without disorder of intellectual development and with mild or not impairment of functional language. So it looks like the authors used DSM-5 to diagnose autism, and then used the philosophy behind ICD-11 amend the DSM-5 diagnosis. Note that the ICD-11 approach has been heavily criticized as researchers have shown pretty thoroughly that there is hardly any correlation between intellectual ability (or IQ) and other symptoms of autism. That is the only reason to specify intellectual impairment at all is so that autistic individuals with intellectual impairment need additional accommodations for their disabilities.
I suspect what happened here is that the reason they specified these two supposed sub-types of autism is political. That they basically took what used to be called Asperger’s and said that was one of two subtypes of autism.
I'd like to preface this by saying I don't feel strongly about the naming issue in either direction.
Initially I figured the authors were using the word "Autism" as used in DSM-5, where it's a blanket term for a range of conditions. But, their repeated assertion of "two types" of autism doesn't line up with that theory: DSM-5 defines three levels, not two.
They definitely aren't using the DSM-IV definition of Autism (the stricter definition that you prefer), and they also aren't following the taxonomy laid out in DSM-5. Where did their definition of Autism come from?
Was it implied that their two-level model was derived from the results of their tests? If so, I missed that part. They mention a correlation between brain overgrowth and severity of symptoms, but they don't mention a clear separation in the test data that would justify classification into two distinct groups.
I understand that DSM isn't gospel, but if they're going to make up their own taxonomy, they should provide some rationale for it.