The whole thing is complicated in the USA because there are two ways of having your child identified as being anywhere on the Autism/Pervasive Developmental Disorder (PDD) spectrum. Some kids are identified in the educational system only, some in the medical system only and some in both. In the educational system an educational category is applied, not a diagnosis. The educational category is called Autism Spectrum Disorders (ASD), autism spectrum disorder. Period. People off the official paperwork may discuss what they feel is the medical diagnosis to be more specific, but it is not ever officially given. Schools do not have to accept a medical diagnosis., they only have to consider the testing etc. when an evaluation is done (of course it will qualify for a 504 plan), and the medical community can poo poo an educational category, and insurance will not pay for autism therapies unless there is a medical diagnosis of Pervasive Developmental Disorder (PDD) of some kind. (unless the child is diagnosis with a symptom that is covered like language delay etc.).
In the medical community the DSM IV is used, and as JJJ said, that is most likely changing and will more closely match the educational system. I think, and if anyone has recently read up on this....that Asperger's might become a separate diagnosis from Autism Spectrum Disorders (ASD)??? I can't remember what the final disposition was on this, when I read they were discussing that option. But for now, the categories are all under the umbrella of Pervasive Developmental Disorder (PDD) (Pervasive Developmental Disorder) the diagnosis subcategories are Autism, Rett Syndrome, Disintegrative Syndrome, Asperger's Syndrome and if a child does not meet criteria for any of these fully but does show traits they are diagnosed with Pervasive Developmental Disorder (PDD)-not otherwise specified (not otherwise specified). Many people call Pervasive Developmental Disorder (PDD)-not otherwise specified high functioning autism, but that is not an official diagnosis and there are kids who do fully meet Autism criteria but are still called high functioning. Since in each category the person being diagnosis only has to meet a certain number of characteristics/symptoms out of the total number in each section, there is a wide number of combinations of symptoms that still will meet criteria. This is why people look so different even though they have the same diagnosis. (and of course because the degree that each person displays a symptom and the specific behavior used to represent a symptom varies too). For all of these reasons it is thought that one diagnosis would be more understandable and allow people who need services to be able to access those more easily. Less people will fall through the cracks I believe. I am glad it is changing. It IS a spectrum disorder....and many people change over their lifetimes too. But they stay on the spectrum usually, just gain skills and lose some symptoms so move around on the "severity" end of things.
I think acceptance is important. It is a lifelong condition. But the other side of that coin (have you read Stanley Greenspan-- floor time stuff, etc...???) is that people may limit their expectations once they think "autism". We all have heard stories of kids who seem very very severely limited, but once a tool is found to help them to communicate or integrate or to connect in their area of interest, etc... the view of that person is changed to being very capable in many areas. Parents can lose hope, even therapists can box kids in. The spectrum diagnosis can give one a realistic picture of how things can vary and all is not lost.
I am all for the change in the DSM, I think it will be so much less complicated and will result in easier access to services.
