Why do many children with ASD have an Intellectual Disability?

Irases by Ray David

Artwork courtesy of Ray David

by Dr Giacomo Vivanti

Many individuals with Autism Spectrum Disorder (ASD) have Intellectual Disability (that is, below average I.Q. and poor adaptive functioning). What is the nature of this association? Data published from a recent study at the Olga Tennison Autism Research Centre (OTARC), Intellectual development in autism spectrum disorders, provide new insight into this complex issue.

The scientific community has given little attention to this question for decades. Indeed, the prevalent view in the field is that Intellectual Disability in ASD is an additional, unrelated condition that ‘happens’ to be present in some individuals with ASD, and is not seen as providing valuable information on the nature of autism.

Following this line of thought, most research in ASD conducted over the past decades, including research on treatment, has excluded individuals with ASD who have an Intellectual Disability, on the ground that their Intellectual Disability would confound the interpretation of results. As a consequence, we don’t have much knowledge on effective treatments for children with lower IQ (arguably the ones that are more in need of help) and we don’t know much about why Intellectual Disability occurs so often in ASD.

However, the data published in our study provide some new insight into this complex issue. Results from a longitudinal analysis of the intellectual development of 80 children with ASD indicate that the risk of developing an Intellectual Disability increases with the severity of ASD symptoms. In other words, those children who are more severely affected by ASD in early development are more likely to have a lower I.Q. later in life.

Child by Ray David

Why is this the case?

Recent research on brain plasticity indicates that brain organization in typical development is critically shaped by the child’s social learning experiences during early development. We propose that the presence of severe symptoms of ASD impedes this process, so that children who are more severely affected are those who are least able to appropriately engage in the social learning experiences that are crucial for normal intellectual development. Therefore, ASD and Intellectual Disability do not appear to be unrelated conditions. Rather, the presence of severe ASD symptoms might be a risk factor for developing Intellectual Disability. That is, the children with “ASD associated with Intellectual Disability” are in fact children whose ASD symptoms are so severe that these preclude them from processing the environmental inputs that ‘sculpt’ brain organization during early critical periods.

From this perspective, we argue that the practice of excluding children with Intellectual Disability in ASD research to study “pure autism unconfounded by Intellectual Disability” is ill considered. Rather, research should target those factors that place affected individuals at an increased risk of negative outcomes, such as the presence of an Intellectual Disability, and understanding the underlying causal mechanisms, to inform clinical practice, with the ultimate goal of fostering positive outcomes for all individuals with ASD.

Hat by Ray David

How to read and download the article

The article Intellectual development in autism spectrum disorders has been made available without cost to you. When you click through to the extract, the top right hand side column provides numerous formats including PDF and full text.

18 Responses to "Why do many children with ASD have an Intellectual Disability?"

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  1. L Morris

    March 30, 2017 at 11:11 am

    As a mum of two boys with Autism & both have an intellectual disability. They are smarter than they are on paper. The report is the opposite of their abilities, however the report is a good indication on where the children need extra help or resources.
    My eldest (17) has an IQ of 70 but yet at high school is achieving very high results because of how he is being taught.

  2. Klas Wullt

    November 10, 2016 at 11:08 am

    Emotional nonsense and retarded experts and psychologists and hysteric ignorant people!
    Under these new rules I am an adult with Autism Spectrum Disorder
    and I am highly intellectual. You fail to understand that there is a difference between retarded intellectually damaged autists and non-retarded highly intellectual autists.
    Psychologists never gathered enough solid scientific data on Aspergers Syndrom
    it was always misunderstood and therefore it doesn’t exist.
    The retarded autists can never transition into highly functioning Aspergers
    with some sort of training or terapy. The scope and function of the disability
    is completly different. The retarded autists have severe inability
    to interact with reality itself and understanding the existence of other people
    the way a normal person or a person with aspergers can.
    Highly functioning people with outdated aspergers
    doesn’t have less autism, they have a different autism.
    I can think, I am sentient, I am even more sentient than normal.
    My brain is abnormally wired for pattern seeking and I understand
    that people exist and reality exists.
    Retarded Austists have severe problems functioning so they don’t
    have any pattern seeking ability or their pattern seeking ability
    only apply to one thing.
    Yes we all have this inability to read faces and read humans
    but a person with aspergers can learn to read people
    People with aspergers have flawed and strange speech and language skills
    but it’s a language skill. We are just stuck with a painful
    and lonely sense of objective knowledge, unable to communicate
    and share our through or being part of others lives.
    Being unable to adapt to society doesn’t mean I am stupid,
    but it doesn’t cause the retardation either.
    Rather some sort of damage or genetic superiority
    affects different parts of the brain.
    My pet theory is that like dogs, Aspergers have been breed by society to be better than Autists, let me explain! Autism creates an all or nothing situation.
    Minor biological changes or other abilities in combination with Autism
    either leads to solipsism and retardation or highly desirable intellectual abilities.
    Aspergers creates many qualities in me that normal people admire
    and has made me a very popular person though I am unable to use them
    be part of the world of other people.
    My ability to learn anything that has some intellectual element is fantastic
    but I can’t adjust to society to develop my talent nor can I use my abilities
    in a profession. No, grammar is not my special interest.
    People with Aspergers have an antisocial learning ability which allows
    us perceive information objective like a human computer.
    Normal people have an pedagogic intelligence based on imitation learning.
    If you don’t have this ability the autist child can’t develop a concept of reality
    or a concept of self. Autism serves as a quality checking mechanism, the environment for survival of the fitters.
    In order to develop into a normal functioning human being
    the autist has to be more intelligent than the average person.
    I have no intuitive abilities, I have no spontaneous unplanned emotions.
    I am entirely like a computer, bad programming goes in and bad shit goes out.
    Everything in my life is intellectual and also terrible chaotic.

    I have meet plenty of retarded austist and high functioning autists in my life.
    You are putting us through hell and many of these new an a trendy theories
    are way behind of what knowledge many adults with Asperger
    has to painfully spend their lives learning.
    You are invalidating our life knowledge and experience because you
    are only investigating underdeveloped people and only look at the subjective value of peoples
    weaknesses and not the patterns of peoples weaknesses.

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