As far as I can tell, the definition of autism coincides with the desire of healthcare to address it without having to carve out 100+ variations of behavioral outcomes to get insurance to pay for it.
We know autism affects all sorts of long term outcomes, but if you tried to split it into actual diagnoses, you end up with insurance companies dividing and conquering approvals.
So instead of having several definitions, we put them all behind autism because that has already received appreopiate laws that establish requirements to treat both at school and in healthcare settings.
So basically, once it breached the "we need to address this", rather than every new diagnosis having to struggle to say "look, this problem effects society", it just grows offshoots and spectrum status.
Because it's definitely not a physically identifiable disability. It's all behavioral and that will always have more coincidences.
You nailed it. I've spoken with doctors who were involved in changing DSM V to have a more inclusive definition of ASD with the express purpose of getting more kids access early intervention that they wouldn't with the PDD-NOS and other diagnoses from DSM IV.
That might be the intent but in practice the opposite has come true. The more narrow definition is more exclusive, which means fewer child with autism can be diagnosed as autistic. For example criteria under the description of Asperger’s and PDA are excluded so those children cannot be diagnosed as autistic and therefore those children cannot receive additional support. That is a massive handicap that requires main streaming children that cannot function or learn in a normal classroom.
I think you might be in the wrong state.
Many states require health insurance cover autism and have their own definitions.
It's definitely a broad sprectrum if the right healthcare system from the State's POV.
So how do other countries other than US define autism?
The UK follows the DSM