Low Functioning Autism vs High Functioning Autism in 2012

There is a great deal of confusion surrounding the terminology simply because of how vague it really is… what exactly is “low functioning” or “high functioning”? Is it to be measured the same as the wattage of a light bulb or the complex calculable abilities of a computer?

For many people, as it pertains to Autism, it can simply be the difference between speaking and not speaking.. for others it can be a difference in perceived IQ levels.

Personally, I’ve always thought of the terms as indicators as to the level of one’s ability to be independent. Can they shelter, feed and provide for themself? Can they maintain a job? Can they “function” in the world on their own?

Whether or not that means using a device to speak for them, high or low IQ levels… what ever. It doesn’t matter… so long as they can live independently, they are “high functioning”. If they can not, they are “low functioning”. I don’t maintain that this is the correct way to think of these terms but simply that it’s how I think of them when I hear them or use them myself.

The reality is though that whether or not you agree with this form of terminology or not, you’re going to have to get used it. As of 2012, the discussion is no longer what it means or how to use it but whether you are using it pre DSM-5 or post DSM-5.

dsm-5Pre DSM-5

Up until the DSM-5, the Autism Spectrum Disorder has always been a list of common disorders such as Autistic Disorder, PDD-NOS and Aspergers Syndrome, which was added in the DSM-IV (IV is the roman numeral for 4).

That means that there really is no low or high level… there’s simply a different disorder to fall into. If you could live independently but struggled socially, you had Aspergers. If you had more severe impairments which left you dependent on others for life, you had classic Autistic Disorder. Others that fell somewhere in the middle would often be PDD-NOS (Pervasive Developmental Disorder – Not Otherwise Specified)

That’s a very general description, it’s far more complicated than that but does give you a good idea.

This is where “low functioning” and “high functioning” terms often become a point of contention among experts, autistics, parents and everyone else.

As we progress further and further, we have become increasingly aware that many people that are unable to speak are actually able to communicate quite well once given the means too.. such as an iPad or “voice box” which can modulate text into speech.

We’ve also come to discover that just because an autistic may score low on a conventional IQ test, they may actually still be very smart. In fact, they could be brilliant. It’s just that the IQ test as well as the communication before, during and after was not done in a manner that was understood by the individual.

So labeling a person as “low functioning” because they could not speak or scored low on an IQ test was very much an inaccurate and inappropriate use of the term.

Post DSM-5

The DSM-5 will be wiping out many of the individual disorders within the spectrum and replacing them with levels… 3 levels. These 3 levels will essentially make up exactly what we will come to know as “low functioning” and “high functioning” and then.. one level somewhere in the middle.

They break down like this:

  1. ‘Requiring support’
  2. ‘Requiring substantial support’
  3. ‘Requiring very substantial support’

If you don’t believe me, you can look it up here: http://www.dsm5.org/ProposedRevisions/Pages/proposedrevision.aspx?rid=94#

While this will once again open the terminology into very vague misinterpretations, especially for those that have never even heard of, much less read, the DSM… it will also attempt to very much define exactly what “low” and “high” functioning is supposed to mean.

Which means that most people won’t know what these levels mean but if someone does use the terminology incorrectly, you’ll now have something to point them to.


I understand the frustration when you read or hear someone using terms like this incorrectly.. or at all really. But at this point, we’ll all have to get used to it.

It’s coming, one way or another. The only difference being that it’s a little more defined. And now there will be three instead of just two.

So the next time you see someone using these terms, check for their accuracy against the actual DSM-5 records… if you can’t stop people from using them, you might as well try to get them to use them correctly.

About Stuart Duncan

My name is Stuart Duncan, creator of http://www.stuartduncan.name. My oldest son (Cameron) has Autism while my younger son (Tyler) does not. I am a work from home web developer with a background in radio. I do my very best to stay educated and do what ever is necessary to ensure my children have the tools they need to thrive. I share my stories and experiences in an effort to further grow and strengthen the online Autism community and to promote Autism Understanding and Acceptance.

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14 Responses to Low Functioning Autism vs High Functioning Autism in 2012

  1. Liz Mellor January 10, 2012 at 9:38 pm #

    Does this mean the terms Classical Autism Disorder, PDD-NOS and Aspergers will no longer be used and the new classification is Autism Spectrum Disorder – Low Level Support Required (ie Low Functioning) and High Level Support Required (ie High Functioning)? What if someone with ASD does not require any support to live independently – are they then considered not to have ASD?

  2. Stuart Duncan January 10, 2012 at 9:51 pm #

    Actually, the official diagnosis that a child would get can be rather wide ranged and varied. They’d look something like this: “Autism Spectrum Disorder with intellectual disability” or “Autism Spectrum Disorder with fluent speech”.

    The 3 levels I mentioned will be a part of the diagnosis to indicate the “severity” of the condition.

    So yes, they’d still be diagnosed. It would just be more a description and severity scale rather than just a name, like Aspergers.

  3. Frango Mint January 10, 2012 at 10:10 pm #

    I am having a hard time figuring out how to tell the difference in level of severity (I guess that’s why you need a PhD to do it, huh). But seriously, what is the difference between “noticeable impairments” in communication (level 1) and “marked deficits” in communication (level 2). They sound virutally the same to me. Also, “difficulty initiating social interactions” (level 1) and “limited initiation of social interactions” (level 2). Very fuzzy.

  4. Emily Willingham January 11, 2012 at 10:35 am #

    My autistic son had a clarification about function that I posted last February (http://daisymayfattypants.blogspot.com/2011/02/from-autistic-boy-different-perspective.html), and some autistic people also commented about it.

    The DSMV terminology reflects a level of support that is quite specific to two criteria–communication and repetitive behaviors–and not related to the more common global interpretation of high or low function as related to intellectual function and activities of daily living. In fact, “support” in the DSMV sense can mean one of the examples you give, of using an iPad because of apraxia of speech. That doesn’t mean the person is low-functioning in the commonly accepted sense of “low intellect” or global low function, which is how most people would interpret that term. Any mention of “function” should be specifically associated with these two categories and level of support and nothing else, which is why “low functioning” and “high functioning,” with their more global connotations, should still be avoided. Specific modifiers, such as “speech function” or “verbal function” would be an improvement and not encompass the whole person in their implications.

    @Frango The severity levels do elaborate on what the differences in those two would be. But I agree that it remains fuzzy and think that it will lead to wide variations in who receives a diagnosis, based on idiosyncrasies of the people making the diagnosis. We’ll see.

  5. Stacy Maynard January 11, 2012 at 10:41 am #

    Great post. I have very strong opinions when people use the term low-functioning vs high-funtioning. I find that people need to use these terms, even if they are extremely mis-understood. I hope that DSM-5 will help minimize some of the confusion. I hate it when my son is classified by the public as high-functioning because he is verbal just like I am frustrated by someone being classified as low-functioning because he is non-verbal. These same two children could be on opposite ends of the spectrum socially. The non-verbal child could be very social as my son struggles socially even though he is verbal.

    I am happy they are taking away the labels, like “Aspergers” as people have a hard time understanding the differences between them all.

    I am in the midst of writing a blog about functioning levels. I’ll let you know when it is complete.

    It is amazing as parents how much we need to learn, eh?

  6. Daniel Comin January 11, 2012 at 4:28 pm #

    Dear Duncan,
    In my opinion this model of diagnostic is a big mistake.How many kind of autism we need to have? One for each person with autism.
    Any person is different, this is the beauty of diversity.
    Congratulations for your web site, I love it
    Warm regards from Spain
    Daniel Comin
    Director and Editor of

  7. Shane February 20, 2012 at 7:10 pm #

    I have recently adopted an autistic child, who is the youngest. According to the doctor, he has no brain function whatsoever. however; he walks, he talks to a certain degree usually 1-4 word sentences, and can count to 10 and knows half the ABC’s he’s in diapers and on the bottle at 6 years old. He ‘s ritualistic and mimics. He does seem to learn however. Apparently he does not posses a long-term memory. But who really knows what’s going on in his noodle? There’s no brain function….at all he’s flat-line. How then can he do all these things and still surprise us regularly? like pick out a movie from multiple choice and with no pictures, only words can identify the movie. He has not been taught to read but seems to posses this ability. Thanks for the great knowledge.

    • Char February 27, 2016 at 5:10 pm #

      Your child is far from brain dead. My advice: Get a new doctor. He is the one that is brain dead.

  8. Riley June 13, 2012 at 5:22 am #

    Very good post. From my experience working with autistic people it’s not always clear what the lower functioning autistics are able to understand. Many times, the lower functioning autistics begin to “bloom” in their 20’s or 30’s, showing us that perhaps many of the characteristics of LF autism are because their unique brains take a little longer to catch up and when they can’t speak it fools us into thinking they aren’t intelligent, when really they are. We have no idea what they really know. For sure, they know more than we can imagine.

  9. C. August 26, 2012 at 12:06 pm #

    I think the terms “high functioning Autism” and “low functioning Autism” are necessary so that we can differentiate and thus understand the individual better, which allows for more accurate services. The problem lies in defining these terms with consistent accuracy. What determines HFA and LFA?? I personally think many traits and characteristics need to be taken into account. My daughter totally seems high functioning, however, she is unable to hold any kind of conversation, depsite being able to put together 8 word sentences at times. She seems unable to truly understand what is being said to her, outside of things said to her on an almost daily basis and learning the meaning of them through repeated exposure to the words and learning what the words are associated with. She gets anxious when family/peers try and talk to her because she doesn’t understand what is being said to her. Half the time she shows desire to socialize, but is unable to adequately. She cannot initiate conversation; when in social situations especially, she parrots speech and the body movements/language of others (echolalia & echopraxia). There are days when she makes vocal stims practically all day long, regardless of what she is doing and/or where she is at, and then there are days when she barely stims at all, including the vocal noises. She does not have much hypersensitivity, rather seems to have a lot of hyposensitive issues; that right there throws people off because she doesn’t seem overly bothered with clothes or lots of people. She does not need severely strict routine, she takes change rather well. Since she can now communicate her needs and wants, and her observations, she no longer screams nearly as much, and her tantrums are usually what just seems like her being a brat because she tantrums when I tell her no, or that she cannot do something she wants to do. There are many things about her that day to day, she seems almost neurotypical. Her autistic traits are more subtle a lot of the time. Somestimes she runs right up to children (getting in thier personal space which then makes them back up), and other times, she seems to want nothing to do with the people around her, she’ll scream if you even look at her. She seems to sway wildly from possibly “low functioning” to “high functioning”. She is 4 1/2 and just now starting to use the potty. She no longer bangs her head, pulls her hair out, eats hair/drywall. She lets me sing to her sometimes now, and does maintain eye contact with me now, although her general eye contact is fleeting, but some people she will look right in the eyes for sustained periods of time, and other people she won’t look in the eyes to save her soul. She does not liked to be hugged or kissed most of the time, but there are times when she comes for hugs and kisses and wants a lot of them at once. She still likes to smack herself in the face, and she has been smelling things lately, where as before she wasn’t. I do flips flops with her. Certain times she seems rather autistic, others times, she seems rather neurotypical. So, where on the spectrum would she fall?? I do not know.

    • A March 17, 2013 at 9:17 pm #

      I am wondering what is her IQ test score is?

  10. Selene Denney (Oceanside, CA) August 12, 2014 at 6:13 pm #

    Hi Mr. Duncan! I am. a graduate student in the area of special education, moderate to severe. In this particular class, we have been able to go over “high and low functioning.” It seems to me that your post was right on. In fact, I never heard of hf-lf until I took this class! I believe that the stigma of hf-lf should be gotten rid of because it doesn’t make too much sense anymore. I will have to continue to read your blog because I’ve learned much from your comment.


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