Intellectual Disability and Autism Spectrum Disorder (ASD)
3 min · Special Needs
July 26, 2023

Intellectual Disability and Autism Spectrum Disorder (ASD)

Intellectual disability (formerly known as mental retardation) is characterized by limited intellectual functioning and adaptive behavior. The former is determined by one’s mental capacity, reasoning, and learning. Standardized intelligence tests, with the Intelligence Quotient (IQ) being the most well-known, are methods for determining a person’s intellectual functioning.

Adaptive behavior is a blanket term for the day-to-day skills that one learns while growing up. It includes practical skills, conceptual skills, and social skills.

Practical skills: These are daily skills relating to personal care, organization, money management, navigating transportation and travel, and using common technologies like telephones and computers.

Conceptual skills: These are skills we might classify as educational skills. They include reading, writing, reasoning, numbers and math, language, and memory.

Social skills: These skills relate to communication, feelings of empathy, and relationships (both friendship and personal).

Children with intellectual disabilities do not always tick all of the adaptive behavior boxes. Some children with an intellectual disability may have a strong practical skill-set and a weak social skill-set. For example, a child may have no difficulty using a telephone or computer but may be unable to form and keep friendships.

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Relationship between Intellectual Disability and ASD

In 2008, the Center for Disease Control (CDC) conducted a study examining the relationship between intellectual disabilities and ASD. They concluded that around 38% of children with ASD also had an intellectual disability. Researchers are still trying to establish if there is a genetic link between the two. Lately researchers found different genes associated with these two formation.

Because intellectual disabilities have such a high occurrence in children with ASD, it is important to determine early on whether or not your child has an intellectual disability. If you suspect that your child with ASD may also have an intellectual disability, the first step will be to have him or her examined by a pediatrician to rule out any physical issues, like hearing loss or visual impairment, which can often cause similar symptoms. Afterwards, a child psychiatrist or school psychologist will conduct one or several standard intelligence tests. An IQ of 70 or below indicates intellectual disability. While a low IQ is a cause for concern, it is also possible that the child with ASD has merely not yet learned the skill sets tested. This is why repeated testing over the years will confirm or refute an intellectual disability diagnosis.

Not all children with ASD and intellectual disability will have the same symptoms or level of functioning. Because adaptive behaviors encompass numerous skill sets, intellectual disabilities can be mild, moderate, or severe depending on how many adaptive behaviors are affected and the degree to which they are affected. Additionally, the treatment plan for ASD may overlap with that of intellectual disability, meaning that whatever special education or assistive technologies already in place are mutually appropriate. Young children, especially, benefit from early intervention, which includes speech-language, behavior, physical, and occupational therapies.

An ASD and intellectual disability diagnosis does not mean that your child will lag behind his or her peers or never develop life skills. On the contrary, with the right support, many of these children are able to achieve life’s milestones and become independent.



  • “” -Srivastava, A. K., & Schwartz, C. E. (2014). Intellectual disability and autism spectrum disorders: causal genes and molecular mechanisms. Neuroscience & Biobehavioral Reviews, 46, 161-174.


This article is examined by Clinical Child Psychologist and Ph. D. Researcher Kevser Çakmak, and produced by Otsimo Editorial Team.

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This post does not provide medical advice. See Additional Information.