Back in February 2011, Jon Brock of the most excellent blog, “Cracking the Enigma,” wrote a post about the current number of variations in autism diagnoses. He explained that the variations are important to researchers in the field, and to understanding autism (and autistic individuals) more generally. He performed a calculation of the different ways (essentially different combinations of symptoms) that can lead to an autism diagnosis under the current DSM-IV, and reached the staggering number of 2027. That doesn’t even include the full range of what has become known as the “autism spectrum,” such as Aspergers and PDD-NOS.
That “autism spectrum” gets the official name (instead of just the five “pervasive developmental disorders”) under the proposed DSM-5, due to come in to effect in May 2013. The proposed DSM-5 makes significant changes to the autism spectrum, such as removing the terms “Aspergers” and PDD-NOS, pushing Retts out of the DSM altogether, and shuffling around the criteria for an autism diagnosis.
Not surprisingly, these changes accompany a change in the number of ways you can get an autism diagnosis. There would no longer be 12 tick-the-box options under category A of the DSM-IV criteria for autism, as discussed in Brock’s post. Instead, under the proposed DSM-5, there are four criteria that must be met for a diagnosis (A, B, C and D). Only criteria B has variations of things an autistic person might or might not have – the variant tick-the-box style that dominated the DSM-IV criteria. Within criteria B there are four options, at least two of which must be present for a diagnosis.
Essentially, the criteria from DSM-IV has been shuffled into a new formation for the proposed DSM-5. By my own breakdown, the proposed criteria A (all of which would be compulsory for a diagnosis) groups together all the current criteria A (1) (social interaction) and some of A (2) (communication). The proposed criteria B (the one with 4 options), is a mix of some of the current A (2) and A (3) (repetitive behaviours and interests), plus a new consideration for sensory issues. The only significant removal from the current criteria, is (2) (a) about a delay or lack of spoken language.
When it gets to the numbers, what all this means is that instead of over 2027 variations for an autism diagnosis under DSM-IV, the proposed DSM-5 brings that number down to only 11.
Considering how much the huge variation under the old diagnostic criteria (even if it had been far less than the number calculated by Brock), can and does affect research and general statements and understanding of autism, that significant drop in variation numbers would be a real game-changer. With just 11 variations, it would be easier to research and draw wider-ranging conclusions about autism and those with an autism diagnosis. It’s an interesting and important change to ponder, putting it into numbers just makes that change more stark and astounding.
A huge thank you to Jon Brock of course for posing the original question and calculating the 2027 number. Another thank you to his commenter on that post, mamafog, for wondering how this would change in the DSM-5 thus prompting me to find out for myself. And an advanced apology if my 11 figure is somehow wrong; I ran the process past my husband who lectures in Economics and he reached the same figure as I did independently, so I’m hopeful that means it’s correct. Do let me know if I’ve made a mistake and where the mistake has been made if you spot one! Thanks.