I never realized there was so much overlap between ADHD and autism until my daughter received both diagnoses during an extensive testing process.
Several years ago, we went to a highly recommended neuropsychologist to get a better sense of the unique way her brain works. When we got the results, I was surprised to see autism spectrum disorder and attention deficit hyperactivity disorder. I didn’t know it was possible to have both.
But now that we’ve lived with this knowledge for a while, I’m often surprised by the similarities. I’ve also learned many of the coping strategies — for parents and for children — that can work for both diagnoses.
Amy Marschall, Psy.D., who herself is dually diagnosed, explains these connections more clearly. Marschall, an ADHD Online provider, is a licensed clinical psychologist based in South Dakota who works primarily with children and adolescents. In 2021, she presented a webinar for ADHD Online on the topic of autism and ADHD.
In this post, we’ll break down the differences and similarities between ADHD and autism, and why an understanding of these nuances can help you better support the children in your life who may have both diagnoses.
The Basics: Defining ADHD and Autism
It’s not uncommon for people to be diagnosed with both ADHD and autism, according to Marschall. In fact, researchers are currently exploring the possibility of the two being the same neurotype — a type of brain, in terms how it works — but presenting with different symptoms, she says.
By definition, autism and ADHD are each a genetic disorder that affects the development of the brain. It’s not a given that you’ll have ADHD if you have autism, or that you’ll have autism if you have ADHD. But you’re more likely to, as having either one increases the risk for the other.
Just how many people have both diagnoses? Statistics suggest one in four people with ADHD also have autism, and two in four people with autism have ADHD – although Marschall believes both numbers may be even higher.
The Major Differences Between Autism and ADHD
According to Marschall, one of the most prominent differences between autism and ADHD is sensory sensitivity. On the whole, sensory challenges — such as preferring or avoiding certain fabrics, sounds, textures and tastes of food — are not associated with ADHD.
Language development is another issue in autism that isn’t associated with ADHD, she says. Atypical development of language among children with autism can go two ways: they may be very delayed (staying mostly non-verbal until age 6, for example) or super advanced (using big words and complex sentences at age 2). Children with ADHD, on the other hand, are generally on track with other children in terms of language development.
Megan Anna Neff is an author and practicing psychologist with an expertise in autism and ADHD. Her website provides extensive online resources about these two developmental disorders. She defines autism as being characterized by challenges with social interaction and communication, and by using repetition and routine to self-regulate. Those with ADHD experience challenges in regulating attention, as well as hyperactivity and impulsivity.
Another area of divergence relates to daily activities. A child on the autism spectrum typically craves routine and what’s familiar, while a child with ADHD craves novelty and new experiences. A graph that Neff created (as part of her Misdiagnosis Monday series on Instagram) shows some of the similarities and differences between the two diagnoses.
Similar Symptoms, Different Presentations
Perhaps one of the most recognized characteristics of autism relates to special interests. Think of the child who is obsessed with trains and knows everything about them or places them in organized rows. These interests are generally sustained over a longer period of time than someone with ADHD, who might be hyperfocused on a project, subject or preferred activity.
Transitions are another area that individuals with either ADHD or autism may find challenging. But according to Marschall, those with ADHD have a harder time getting started on the new thing and shifting focus. Those with autism struggle with changes in routine and tend to be more rigid, desiring predictability. For those with ADHD, novelty — or new things — are always more interesting, says Marschall. For those with autism, new things can be distressing or upsetting.
“ADHD and autism, classified as neurodevelopmental conditions, impact how the brain processes sensory input and cognitive processes,” says Neff. “Both impact executive functioning, attention processes and sensory processing.”
There are other overlapping traits between ADHD and autism. They include time perception, emotional regulation, social difficulties and repetitive movement, or “stimming.” For the ADHD child, that may look more like hyperactivity or fidgeting.
According to material on Neff’s website, reading social cues is difficult for individuals with either diagnosis, though for different reasons. For the child with ADHD, challenges with focus and attention are the primary reason they miss — or misread — social cues. Those on the autism spectrum struggle with translating and understanding social cues not because of lack of focus or attention but just because of the way their brain works.
Why Get a Diagnosis? The Pros and Cons
If you’re pursuing a diagnosis of ADHD, autism or both for a child in your life, here are some things to consider:
First of all, a diagnosis is rarely a simple, straightforward process. According to Neff, a person may not meet the criteria of both and yet still have significant trait overlap. She also suspects that “pure ADHD” or “pure autism” is the exception, not the norm.
There are also valid concerns among parents, teachers, providers and peers about labeling or even “overdiagnosing” a child.
“If they’re denied access to certain jobs because of a diagnosis, that’s an understandable concern,” says Marschall. “It’s a hard balance to strike.”
But if certain supports, services, medication or therapy treatments are needed — either in school, at home or in the community — getting a diagnosis or diagnoses is key.
Also, since there’s a genetic component to ADHD and autism, it may be worth pursuing a diagnosis for yourself if your child has been diagnosed (or is being evaluated for it).
“You’re never too old to get tested,” says Marschall. “And it’s not a personal failure on your part; it’s just about getting the services you or they need.”
Pursuing any diagnosis will depend on a peron’s motivation, and how helpful they think it might be, Marschall says.
How to Support Someone with ADHD, Autism or Both
Ultimately, ADHD and autism are different ways of thinking, feeling and being in the world. They both color everything that people who have them do and see. And it’s a spectrum. Like paint, there’s a variety of hues that correspond to one solid color. Pink can be a bright, bold fuchsia, or a soft, pale peach — or any shade in between. Think about going to Home Depot for paint; even a basic white comes in eggshell, gloss, flat, satin and more.
When it comes to these common neurodevelopmental disorders, there are similarities and differences. Some are subtle; some are striking. What matters most is finding the solutions — whether it’s medication, therapy, coping skills, school supportive services or a combination of them all — that works best for each unique child, teen or adult.