Autism and IQ: Intellectual Disability Rates and Test Profiles

Autism spectrum disorder (ASD) and IQ are separate dimensions. Autism is a developmental condition characterized by difficulties with social communication and by restricted interests and repetitive behaviors, and some autistic people have an intellectual disability while others have an IQ above average. Intelligence tests, however, tend to show large gaps between strengths and weaknesses (an uneven profile), and the numbers are known to change considerably depending on which test is used. This article draws on the latest statistics and research to lay out how autism and IQ are related.

The IQ distribution in autism: about 4 in 10 have an intellectual disability

In the 2025 report from the US CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network, 1 in 31 8-year-olds had been identified with autism as of 2022. Of the 5,292 autistic children with IQ data, 39.6% had an IQ of 70 or below (the intellectual disability range), 24.2% an IQ of 71 to 85 (the borderline range), and 36.1% an IQ of 86 or above (the average range or above) (CDC MMWR, Shaw and colleagues, 2025).

The 2020 data are from Maenner and colleagues (2023). These figures come from records of 8-year-olds in the US, and the proportions vary by country, age, and how broadly the diagnosis is defined. The Autism Society of Japan explains that about half of people with autism are reported to have an intellectual disability (Autism Society of Japan). IQs in the borderline range are covered in What is borderline intellectual functioning?.

How Asperger's syndrome and high-functioning autism relate to ASD

The DSM-5, the American Psychiatric Association's diagnostic manual revised in 2013, merged what had been autistic disorder, Asperger's disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified into "autism spectrum disorder" (APA, "Highlights of Changes from DSM-IV-TR to DSM-5"). Current diagnoses add a specifier for "with or without accompanying intellectual impairment" (CDC).

What used to be called "Asperger's syndrome" or "high-functioning autism" was mainly autism without intellectual delay. Materials from Japan's Children and Families Agency likewise explain that "high-functioning" refers to the absence of intellectual delay (Japan's Children and Families Agency, "Major developmental disorders"). Note that "high-functioning" is not a term for high intelligence, and it does not mean that someone's difficulties in daily life are mild.

The uneven WISC profile: high Block Design, low processing speed

Intelligence tests of autistic people are known to show large differences between subtests. A study by a Japanese research team that compared four editions of the WISC found that, regardless of intellectual level or diagnostic category, Block Design (a task of assembling patterns from blocks) was consistently high and Coding (a task of quickly copying symbols) was consistently low (Takayanagi and colleagues, 2022).

Looking at WAIS-IV and WISC-V indexes, an analysis pooling 18 studies and more than 1,800 people found that verbal and nonverbal reasoning were in the average range, while processing speed was roughly one standard deviation (15 points) lower and working memory also somewhat lower (Wilson, 2024).

The Full Scale IQ is an average across an uneven profile, so for someone with large gaps, the Full Scale IQ alone does not capture the real picture. How to read each index is covered in how to read WISC results, and what processing speed involves in how to train processing speed.

Raven's test gives higher scores than Wechsler tests

One study showed that the test used to measure intelligence can dramatically change how intelligent autistic people appear. Thirty-eight autistic children scored an average of 30 percentile points higher on Raven's Progressive Matrices, which asks you to find the rule in a set of figures, than on a Wechsler intelligence test, which relies heavily on spoken instructions and responses, and some scored more than 70 percentile points higher. Non-autistic children showed no such gap, and adults showed the same pattern (Dawson and colleagues, 2007, Psychological Science).

The study suggests that tests that rely on language can underestimate autistic people's reasoning ability. The format and history of Raven's test are covered in What are Raven's Progressive Matrices?, and how to solve matrix reasoning problems in matrix reasoning tips.

How many autistic people have savant skills?

Savants, who show outstanding ability in a specific area, are often discussed in connection with autism. A study of 137 autistic people (mean age 24) found that 39 of them, or 28.5%, had either a savant skill or an exceptional cognitive ability on testing. The most common exceptional test ability was Block Design, and none was found in people with a nonverbal IQ below 50 (Howlin and colleagues, 2009).

The image of autistic people as having special talents applies only to some, but it is also true that many have clearly defined areas of strength. More detail is in What is savant syndrome? and neurodiversity.

An IQ test cannot tell you whether you are autistic

Autism is diagnosed by a physician, who uses interviews, behavioral observation, and a developmental history to judge whether difficulties with social communication and restricted interests or repetitive behaviors have been present from early in development and are interfering with daily life. Intelligence tests are not diagnostic tests for autism; they are used to judge whether there is an accompanying intellectual disability and as material for planning support that fits a person's strengths and weaknesses. The same goes for online IQ tests: they cannot tell you whether you are autistic.

How to check your own reasoning ability with figure-based questions

Nonverbal, figure-based questions give a guide to reasoning ability that is less affected by strengths or weaknesses in language. BrainRank's free IQ test presents 20 questions (about 10 minutes) across four domains, spatial reasoning, pattern recognition, logical reasoning, and classification, all as figures, scores them using item response theory (IRT), and returns an estimated IQ on a mean-100, SD-15 scale along with your strengths and weaknesses by domain. Taking it is free with no signup; viewing the results, including the estimated IQ, is a one-time payment of ¥300 (tax included), with no subscription or auto-renewal (the result can be reopened for 24 hours after it is first shown, and saved as an image or PDF during that window). Results are estimates for entertainment and self-understanding, not a medical or diagnostic assessment.