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The Difference Between Autism

By April 12, 2011

Yes, the grammatical error was intentional!

Autism Awareness Month is a great time to get out the word about issues in autism.  One of the toughest for everyone, including people on the spectrum, parents, teachers, therapists and doctors, is the incredible disparity among people with autism.  How do you make the world aware of a single disorder that can present itself so very differently in different individuals?  How do you create policies, undertake research or provide services for a group of people who have radically different needs?  How do you plan a school program, provide therapies, or even access support when your situation is practically unique?

Of course the answer is - there is no one "autism," and that issue lies at the heart of many of the problems experienced by members of the disparate group that is sometimes called the "autism community."

Some of the biggest differences we face include -

  • Differences in physical symptoms.  Some people with autism also have serious physical problems including (but not limited to) sensory dysfunctions, seizures, gastrointestinal problems, sleep issues and food allergies.
  • Differences in functional level.  One person with autism is brilliant, intense, extremely anxious and often depressed.  Another is non-verbal and physically aggressive.  A third is low-key, affectionate, verbal, but lacking in social and communication skills.  Which of these people is most functional?  The answer isn't always obvious.   What is obvious is that these people can't do the same things, don't need the same supports, and have very little in common as individuals.
  • Differences in onset of the disorder.  Particularly for parents of children with autism, differences in personal experience can create huge rifts.  While one parent saw her child "descend" into autism almost overnight, another sees that her son, who has always been different, is also an awful lot like Uncle Bill - the brilliant but quirky engineer.  Differences like these are causing huge battles over questions like "what causes autism?," "can autism be prevented?"  and "is autism a difference or a disability?"

So what are the different types of autism?  How different are they from one another?  Unfortunately, even the official categories of autism (there are five) don't make clear distinctions.  And those categories will likely be reduced to just three when new guidelines for diagnosis are put in place in 2013.  Here are some definitions, though, that may help families better understand "the difference between autism."

Types of Autism

What Are Pervasive Developmental Disorders?

"Pervasive Developmental Disorder" is a formal term that means exactly the same thing as the less formal "autism spectrum disorder." As with the autism spectrum, the group of disorders described as pervasive developmental disorders includes autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), Asperger syndrome, Childhood Disintegrative Disorder and Rett Syndrome.

What Is Asperger Syndrome?

Often called "the little professor" or "geek" syndrome, Asperger syndrome describes individuals at the highest-functioning end of the autism spectrum. Unlike other autism spectrum disorders, Asperger syndrome is often diagnosed in teens and adults.  People with Asperger syndrome generally develop spoken language in the same way as typically developing children, but have issues with social communication that become more pronounced as they get older.  Because people with Asperger syndrome are often very intelligent - but "quirky" - the disorder is sometimes nicknamed "geek syndrome" or "little professor syndrome."

What Is Mild Autism?

The term "mild autism" is not an official diagnosis. It's simply a more descriptive term than "Asperger syndrome" or "autism." Generally speaking, when people use the term mild autism they are referring to individuals whose symptoms fit an autism spectrum diagnosis, but who has strong verbal skills and few behavioral issues. Those individuals may, however, have significant problems with social communication. They may also have problems coping with too much sensory input (loud noise, bright lights, etc.).

What Is High Functioning Autism?

Like "mild" autism, high functioning autism (sometimes shortened to HFA) is a made-up term that's become more and more commonly used.  HFA is a tricky term, because it can be hard to distinguish a person with HFA from a person with Asperger syndrome.  The official distinction is that people with HFA had or have speech delays, while people with Asperger Syndrome have normal speech development.  But there may also be very real differences in terms of social awareness, personality characteristics, and other traits.  The jury is still debating the fine distinctions.

What Is PDD-NOS?

"Pervasive Developmental Disorder Not Otherwise Specified" is a mouthful of words that are often applied to people on the autism spectrum. It describes individuals who don't fully fit the criteria for other specific diagnoses, but are nevertheless autistic.  Unfortunately, there is no easy way to define the symptoms of PDD-NOS, which may range from very mild to very severe.  As a result, the term is rarely used outside of practioners' offices.  Most parents, therapists and teachers prefer to use more descriptive (though less official) terms to describe their children, students and patients with PDD-NOS.

What Is Severe Autism (Autistic Disorder)?

Severe autism is officially termed autistic disorder.  It goes by many other names, though, including profound autism, low functioning autism, or classic autism.  People with autistic disorder are often non-verbal and intellectually disabled, and may have very challenging behaviors.

What Is Rett Syndrome?

Rett syndrome is a genetic disorder that affects only girls.  It is the only one of the autism spectrum disorders that can be diagnosed medically (so far).  Girls with Rett syndrome develop severe symptoms including the hallmark social communication challenges of autism.  In addition, Rett syndrome can profoundly impair girls' ability to use their hands usefully.

April 12, 2011 at 11:28 am
(1) Jennifer says:

I can very much appreciate your article. I have been struggling for a few years with my 9 year old daughter’s diagnosis. However, my struggle rests with her NOT being deemed to be on the “spectrum”. They say, her level of imaginative play is “too high” to “fit” a diagnosis of Autism or any ASD or PDD. Instead, they have said she is “mentally handicapped”…yes, in the 21st century they used those words. Unfortunately, where we live there is no support group, no program, for such a diagnosis (later softened to “developmentally handicapped”). My heart breaks for her as people stare and criticize and look at me as though I simply have a misbehaved child. Even in school, where she has a full time TA and a IPP in place, they punish her for her behavior as they would any other child. I am not convinced that she is not Autistic and have nothing but love and support for all those who struggle on a daily basis as we do.

April 14, 2011 at 8:57 am
(2) Sheri says:

First of all, great article. Thanks so much for posting it.

I have two sons diagnosed with Asperger’s Syndrome and Anxiety Disorder. Both are amazingly creative. My older son loves to act and is quite excellent at it. He has been in a number of plays and musicals. Both of my sons love to make videos, build with legos, and write stories in either comic book or written form. Creativity is a strong part of who they are, as is Asperger’s Syndrome. They still don’t get the social interaction part of life and can’t read social cues.

My guess is that the person who said your daughter’s imaginative play didn’t ‘fit’ doesn’t know enough about the subject. She sounds like she may well fit the diagnosis for Asperger’s Syndrome.

For both of my boys, things were at their worst between ages 9-11 because the kids around them developed socially while my kids social skills lagged significantly. For both of my sons. their anxiety skyrocketed because they KNEW they weren’t fitting in, but they didn’t know WHY.

Find an evaluator who really KNOWS how to diagnose. I suggest finding a local Autism support group. Yahoo has a number of groups in their Yahoo Forums who might be able to help you. When I finally linked in with a local Yahoo Forum from my neighborhood, I was finally able to find the support I needed.

Good luck, and hang in there.

April 12, 2011 at 11:50 am
(3) autism says:

Jennifer, IMO creativity is part and parcel of autism for MANY people, including talented autistic writers, artists, musicians and actors. My son is upstairs right now designing new, innovative structures with his lego sets (which he mixes and matches after building “assigned” structures).

I’m so sorry for your frustrations!

You might consider finding a private evaluator who has a better understanding of the breadth of the autism spectrum.


April 12, 2011 at 3:45 pm
(4) Sandy says:

Actually, the difference is, is when people started using the ‘autism spectrum’ to describe the whole of the PDD’s. Although every one is different, there is a bases for each of the PDD’s and the criteria is pretty specific. The difference also is how much do co-morbids play a part in whatever diagnosis. That really doesn’t make a ‘different’ autism any more than a child who had a broken leg would. The co-morbids makes it more difficult for the child who has autism.

I am sorry that Jennifer is having a hard time, but due to the criteria, lack of spontaneous make-believe play or social imitative play is specific criteria and it could very well be any child who doesn’t meet any of the PDD’s, it just might not be that and it wouldn’t be considered a ‘different’ autism. Many other disorders can mimic autism. If a different doctor would diagnose autism when a child doesn’t meet the criteria, or even to suggest one might is inaccurate and if any do, then it further proves the rates are there due to the need of a DX for services and such, and further contributes to the confusion as to just what the PDD’s are.

My child get’s in trouble in school too, and has an IEP. That IEP, it wouldn’t matter if it was autism listed or any other, he’d probably still get in trouble. Autism just doesn’t prevent that. Where it matters is suspensions or when it interferes with FAPE. I think we live in a world where socially, everyone expects perfect behaved children, disabled or not.

April 12, 2011 at 3:47 pm
(5) Dadvocate says:

I think it’s too early to fine tune autism subtypes but it’s a very good thing that the recognition of subtypes is becoming the consensus view. I think Chez got it right (for the current state of scientific understanding) with his 4 broad subtypes:

Subtype Onset
Non-regressive (Birth-12mo)
Regressive (>12 mo >18 mo or >24mo
Asperger’s (no regression)
Secondary ASD (result of brain injury, epilepsy, Rhett’s, Fragile X, etc)

He goes into detail on his different treatment protocols for each subtype in his recent book but keeps in mind that each individual needs individual, not a “canned”, treatment.

I’m glad you wrote this piece and hopefully more media types start to report in a way that that recognizes this concept. A good start would be for reporters to insert the word “some” before autism in just about any story they do.

April 12, 2011 at 4:38 pm
(6) autism says:

Dadvocate – those groups would leave out my son, dx with PDDNOS, because his symptoms became obvious when he was about 18 months, but not because of regression. Essentially he ceased to keep up with his peers in language and social development. By the time he was 3, the differences were significant enough to warrant a dx. I don’t think our situation is unique.


April 15, 2011 at 3:52 pm
(7) Dadvocate says:

Lisa – My view is that you can think about regression in a couple of ways. First the noticeable loss of skills like specific words, pointing, etc in favor of perseverative behavior, which my son presented around age 2 1/2. Interestingly, some of these skills would mysteriously, and fleetingly, return from time to time only to disappear again for months (fevers tended to allow him to find these skills again…odd, no?).

I think the other way to think about regression, which my son also presented (which sounds similar to yours) is a marked deviation from a typical kid’s skill acquisition “curve” starting in the toddler years, i.e slower and flatter skill development trajectory. I’m not a pro by any means but I think many of the PDDNOS dxs probably fall into the “regressive” subtype. Clearly, these need to be fine tuned as the science develops but the acknowledgement of subtypes really needs to become more prevalent in the media so pieces like this are important. The absence of using the qualifier “some” in front of “autism” has caused no end of talking past one another within our community.

April 15, 2011 at 5:11 pm
(8) autism says:

Dadvocate – I could buy into that definition, though I have no clue as to whether it defines most people with PDDNOS diagnoses…

But typically “regressive autism” is described as a sudden, acute event – often connected with vaccines. Eg, Joey was developmentally typical on Monday, had a vaccination on Tuesday, developed a high fever and other physical symtpoms Tuesday night, and was autistic on Wednesday.

I guess that we’d wind up with subgroups of “regressive” autism, with “acute” and “not so acute” and so forth…


April 12, 2011 at 4:45 pm
(9) autism says:

Sandy – “the PDD’s” and “the Autism Spectrum” are essentially synonymous terms.

IMO some of the difficulty arises when the criteria are misused, as happens often. For example, someone who overcame a language delay may be diagnosed with Aspergers – when they should really receive a PDD dx. In addition (we’ve disagreed on this before), according to experts the autism diagnosis IS appropriate even when the cause of the issues is well known and involves physical injury (so long as the injury occurred prior to age three).

On an unrelated point, if we define autism as a disorder which makes it impossible to have or show imagination, affection or creativity then we’re talking about a relatively small group of people. Certainly there are many, many people with autism spectrum diagnoses who are radically creative and extremely affectionate.

Perhaps the question is – should such people be diagnosed on the spectrum? If the answer is “no,” we’ll have to recount the number of diagnosed folks, and the number will shrink considerably!


April 12, 2011 at 5:54 pm
(10) Sandy says:

Maybe it’s that small group of people who actually then would have the true definition of autism as described by the DSM criteria and the rest who is extremely affectionate and imaginative are the ones within that misused criteria. When you have that child who fits the DSM criteria to a T, you clearly can see the difference between that child and another.
“For example, someone who overcame a language delay may be diagnosed with Aspergers – when they should really receive a PDD dx.”
That’s a bad, confusing example. Asperger’s is part of the current PDD’s.

I actually don’t think subsets really make a difference other than for cause purposes and cause more confusion. Regardless of onset, the symptom’s are pretty much defined overall per the current PDD’s. My child would and did show the same symptoms as another child who regressed. Do they have a different autism than another, is the question and my opinion they are the same. It’d be the same as would it really make a difference at what age ADHD presented? Or bi-polar? Would onset make those disorders ‘different’?

April 12, 2011 at 6:16 pm
(11) autism says:

sorry, when I said “For example, someone who overcame a language delay may be diagnosed with Aspergers – when they should really receive a PDD dx.” I meant PDD-NOS.

Setting that aside, I strongly believe that the people we are presently diagnosing with ASD’s are NOT homogeneous.

The evidence seems reasonably strong that there are at least one or two disorders lumped in there that have significant physical symptoms.

There also seem to be disorders that involve extremes of anxiety and mood disorders, OCD, etc. Perhaps some of those who are self-abusive or prone to massive tantrums would fall into that category.

There are many who, despite having the ability and desire to communicate either can’t or won’t use the spoken word.

Then there are people who are literally “bright but quirky,” and folks who, like my son, have significant speech and social delays but few other symptoms.

It certainly wouldn’t trouble me if the next DSM was MUCH more restrictive about ASD diagnoses. Instead, however, I suspect we will see even more people lumped in as having an ASD – despite the extreme differences in their symptoms.

I just don’t believe that these are all manifestations of a “spectrum disorder” that is caused by (or treatable by) the same things.


April 12, 2011 at 7:29 pm
(12) Dee says:

And that’s why I love you, Lisa! Not to kiss up but as you might know from my other posts, my son was Dx-ed at 2yr– 9 months ago and my daughter who is now six is flirting with a dx (interesting article on Asperger’s vs HFA: http://www.springerlink.com/content/t3310003584652rt/).

Clearly my family has genetic issues (FX premutation, some other pathways and genes) but there is some strong evidence of environmental interplay. And you cover it all! There isn’t, IMHO, a blog out there like this one! Thank you.

This is also being discussed in all of the journals right now as we get closer to 2013. Dadvocate, another category that has been determined is the plateau onset… as Lisa describes, the child doesn’t make the next jump. A review paper out this year defines the onset and takes a look at outcomes… one study suggests that regressive accompanies the GI issues (as in our case) but another says no. The sample sizes are always too small!

Like you, Lisa, I am looking forward to the aggregation of all of this information so that we have a better understanding. Going back to a much earlier post, all I can do is read, read, read and say what I believe.

April 13, 2011 at 1:22 am
(13) Malia says:

Very well written article, Lisa. I think lack of absolute clarity in defining disorders is something that plagues many of the descriptors in the DSM, although none are currently receiving as much attention as those various definitions on the autism spectrum. I anticipate that diagnosticians in this area are going to have quite the time settling in to a consistent interpretation of the new DSM just as there have been apparent inconsistencies in interpreting the DSM-IV criteria. Perhaps I’m a pessimist, but I think this will be a topic of interest among members of the autism community for several years to come yet.

April 13, 2011 at 8:09 am
(14) davidn says:

When I went to elementary school in the 1960s, I had never heard of autism. There were kids in the school that were considered a little weird. We also heard of kids that didn’t go to school, but were in “homes” or institutions. My simple way of classifying autistic kids today is, would they be the weird kid in school or in the institution.

April 13, 2011 at 4:43 pm
(15) kathryn says:

davidn – seriously that is one of the stupidest comments i have ever read in my life. ‘your way’ of classifying autism is neither insightful or helpful just stupid.

April 13, 2011 at 5:32 pm
(16) Harold Rongey, Ph.D. says:

I believe the healthy brain will be free of autism. The type of deficient nutrients will dictate the specific symptoms of autism that may be experienced. There have been at least sixty nutrients found to be low or missing in those with some form of autism. Interestingly when the missing nutrients are provided in adequate amounts, the symptoms for the most part have been reported to disappear in one to four weeks.

April 14, 2011 at 11:37 am
(17) Eileen Dooley says:

Harvey, I’ve been very active in Asperger/HFA support groups for years, and met Lisa through one of them, ASCEND. Thank you Lisa for all you do to get reliable information out there. Harvey, based on my experience and those of most of the people I know with a child with autism, the nutrition theory does not hold. EVERY family I have run into with a child with an autism diagnosis agrees there are more than one other with similar traits throughout multiple generations in the family, regardless of nutrition, parenting style, education or socioeconomic status. I just finished reading Proust and the Squid and highly recommend it for some wonderful insights (from a mother of a child with ADD) into how brain development or structure affects abilities that may develop in a way disproportionate to the current society’s definition of “normal” or desirable, but which have their own usefulness and beauty.

April 14, 2011 at 11:44 am
(18) Lisa says:

Hi, Eileen! Nice to “hear” from you again!

Hope all is well.


April 14, 2011 at 2:30 pm
(19) Harold Rongey, Ph.D. says:

I had two families, one in Minnesota and one in Australia.
Each family had ten children. In one there were two children with autism and in the other all ten were affected. This looks like genetics but what I found was that the two ate diets that did not include the foods containing cholesterol. The other family–all ten avoided the cholesterol containing foods.
Of now more than 900 individuals with autism, I found well over 90% avoided the cholesterol containing foods.
The difficult part of the genetics approach is to understand how the genetic defect is corrected in those individuals who lose the symptoms when the diet is changed to provide adequately for the known needs of the brain.
The easiest way to see the problem is to take a look at the chemical composition of the brain compared to the composition of the diets of those with autism and one finds the sixty plus nutrients lacking in those with autism.

April 14, 2011 at 11:18 am
(20) Sandy says:

It’s not very nice to say davidn opinion is anything. He has a valid point that many make, people didn’t hear about autism in the 1960′s even though we know it was there (ARI was founded in 1967) and people in those days sent those kids to “homes” or institutions which made it even more less likely anyone would see or hear about autism.
I also imagine peers of my son woud consider my son the weird kid in school.

April 22, 2011 at 9:14 am
(21) Poornima says:


I think the article you posted is definitely informative but I still feel that there are cases like my 3 year old daughter Ishaani, who is right now diagnosed as a case of “neuro regression” and I am not sure which category of PDD she falls in. her symptoms overlap. I am from India. She lost most of her previously acquired skills at the age of 1 year 10 months after which the regression was so quick! All my research on the internet brought me to autism and related spectrum and I got her tested for Rett but she tested negative for Rett symdrome MeCP2 test. She is now 3 years old and bed-ridden without being able to do practically anything by herself. She is a rare case I am told, so I’m actually searching for information that may help clearly identify what her condition is. it is such forums that I look forward to for getting some help. thank you

April 26, 2011 at 2:33 pm
(22) Brianna says:

Great article i have an 11 year old brother with severe autism so when i noticed this article i had to read it.

April 30, 2011 at 12:34 am
(23) Lisa O says:

Thank you for this article. I am a Parent Educator and present a lesson on ASD after my lessons on brain development, infant development, and toddler development. It is an opportunity to debunk some of the myths, discusss the current theories, encourage parents to seek out early intervention screenings if they have a concern about their child, and do my part to educate the public that ASD children are so much more than “the weird kid” in school (to reference an earlier post).

I am also the mother of a 17 year old boy who was diagnosed with PDD-NOS last fall after 12 years of searching for a diagnosis. Part of what made getting a diagnosis so hard in our case was that we have been working intensively with our son since he was 2 or 3. My undergraduate background is in early child development, so we did our best to address what we observed in an environment that offered no understanding or support. As result, my son has learned some social rules and can do things such as making good eye contact–because we taught him. It made it harder to evaluate him this far along into his life.

The good news is that along with this diagnosis comes new ways to help him learn and have a good life. We seem to have been a little ahead of the curve–I look forward to seeing the wonderful things we all can develop to help kids like my son have successful adult lives.

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