Functioning Levels, Support Needs and Other Ways of Classifying Intellectual and Developmental Disabilities #AtoZChallenge

Hi everyone. For my letter F post, I am going to talk about functioning levels and related ways of classifying the severity of intellectual and developmental disabilities. Most of these are highly controversial within the developmentally disabled community itself.

First are functioning levels. These can be described in several ways. With respect to autism, there is of course high-functioning and low-functioning. The distinction between these is not at all clear: does high-functioning mean an at least average IQ, the ability to speak or the presence of relatively few autism symptoms? In any case, these are often very confusing.

An alternative approach suggested by some autistics is to speak of high, moderate or low support needs. I, according to this classification, would be considered as having high support needs even though I’m considered “high-functioning” in at least two of the aforementioned ways (speech and IQ).

Some people have proposed yet another classification, not based on support needs or apparent functioning, which are after all based on a (presumably neurotypical) professional’s assessment, but on masking. Masking is the ability to hide one’s disability-related symptoms from the public. In this sense, “high-functioning” individuals are considered high-masking.

In intellectual disability without co-occurring autism or other neurodivergencies, functioning levels are slightly more useful than in autism, in that they are based on IQ and level of adaptive functioning. In this classification system, someone with an IQ between 50 and 70 (or 85 in some countries, such as the Netherlands) is considered mildly intellectually disabled. Someone with an IQ between 35 and 50 is considered moderately intellectually disabled. An IQ between 20 and 35 puts someone in the severely intellectually disabled range, and an IQ below 20 puts someone in the profoundly intellectually disabled range. That being said, having had my IQ tested many times, I wonder how well IQs below like 50 can be measured on standard intelligence tests. I guess for more severely disabled people for this reason, professionals prefer the term mental age. Like I said yesterday, this is considered discriminatory.

4 thoughts on “Functioning Levels, Support Needs and Other Ways of Classifying Intellectual and Developmental Disabilities #AtoZChallenge

    1. Honestly, while I understand your sentiment, the reason for all the different classification systems is that none adequately capture the diversity of support needs among individuals with intellectual and developmental disabilities. I forgot to say in my post that most autistic activists actually advocate for specific need descriptions rather than saying “high support needs” or “low functioning” in general. For example, someone would be encouraged to say that they need someone to bath them, but they can dress themself with verbal instructions. This, indeed, is how the long-term care funding application form works, but then again it’s looong.


  1. I’ve heard most of these terms. Thanks for pulling them together in one post. That helped me understand how and why people might use them.

    Liked by 1 person

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