ADHD vs Autism in Adults: What are the Differences

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ADHD (Attention Deficit Hyperactivity Disorder) and Autism can sometimes concur. People with either autism or ADHD can struggle with social skills, be constantly “on the go” and fidget.

Jessica McCabe made a video for her YouTube channel, How to ADHD, with Dan Jones (he has autism, ADHD, dyslexia and OCD) from The Aspie World where they discuss some differences between ADHD and ASD (Autism Spectrum Disorder). Some of these differences are outlined in this post.

What are the differences between autism and ADHD in adults?

Types of Disorder

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ADHD is not a spectrum disorder because it is believed to consist of only two types (ADHD and ADD). Autism is a spectrum disorder because there are many types of it such as Kanner’s autism or classic autism on the lower end of the spectrum and high functioning autism and Asperger syndrome on the higher end of the spectrum. From 2013, people who have displayed symptoms of Asperger syndrome or Kanner’s autism have been given the official diagnosis of ASD.

Meltdowns and Shutdowns

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Dan describes a meltdown as “an outburst of emotional energy that is pent up inside you” whereas a shutdown is “trying to cope with emotional over-stimulation but trying to hold that in, so you’re pushing it down.” Dan also says that people who experience shutdowns lose their sense of hope. Jessica also experiences meltdowns, but they don’t last as long for her as they do in people with autism.

Ability to Speak

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People with ADHD often have the ability to speak and can talk too much, but many people with autism are unable to speak or can have speech delay. People with autism who are able to speak may have an immense vocabulary, but not know what some words mean.

Communication Difficulties

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Besides having the tendency to talk too much, people with ADHD may “not notice how their words affect other people” and “interrupt others” whereas people with autism may find it difficult to express “their emotions and thoughts,” have trouble understanding common everyday expressions, avoid eye contact, recoil from physical contact such as hugging or a touch on the shoulder, focus on one topic of interest and “not respond to or initiate to social interactions.” People with autism may also misinterpret the tone in which things are written, such as e-mails.

Social Difficulties

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Jessica says that she learnt things more slowly than her peers did, such as “when it’s appropriate to say something.” Dan on the other hand has no idea how to position himself in order to give the person next to him some space. He also struggles with reading facial expressions and interpreting someone’s tone of voice. Jessica says she cannot tell if a friend is upset because she gets distracted.

Routine and Structure

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People who have ADHD may find it difficult to do the same things every day because they can get bored easily while people with autism may want to adhere to the same routine every day.

Interests and Attention

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People who have autism or ADHD can hyper-focus on a particular subject that they have an intense interest in; however, those with ADHD can easily become distracted if they focus on the same thing for too long. Those with autism can struggle to focus on topics that they have no interest in and engage in subjects that cover these topics.

Sensory Issues

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Dan’s occupational therapist told him that he had proprioception issues from sensory processing disorder when they suspected he had dyspraxia. This is because Dan said he missed the table when putting drinking glasses down. He also accidentally hit himself with the cupboard door whilst removing the glasses because he didn’t know how far away the cupboard door was from him. Dan is sensitive towards certain smells, lights and sounds. He further says that these issues can lead to meltdowns and shutdowns. Jessica does not like to have a lot of tight things on her.


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Overstimulation can manifest differently in individuals with ADHD and autism, due to the distinct nature of these conditions.

In someone with autism, overstimulation often leads to heightened sensory sensitivities. In fact, they may become overwhelmed by specific sounds, lights, textures or crowded environments. Emotional dysregulation can also occur – resulting in increased anxiety, irritability or meltdowns. Hyperactivity or repetitive behaviours, such as stimming may be observed as coping mechanisms for this. Finally, communication challenges may arise, and the individual may exhibit repetitive behaviours or seek isolation as a coping mechanism.

In individuals with ADHD, overstimulation primarily affects their ability to maintain focus and regulate attention. They may struggle with filtering out distractions and staying on task. This can lead to restlessness, impulsivity and difficulty concentrating. Hyperactivity may also be more prominent with fidgeting, excessive talking or constant movement.

Exceptional Individuals webinar: Autism V ADHD 

Nat Hawley, Head of Community at Exceptional Individuals, hosted a webinar about the differences between autism and ADHD.



While the main differences between ADHD and autism are the types of disorder; causes of meltdowns; the ability to speak; communication difficulties; routine and structure; and interests and attention, they are similar in terms of being incurable neurological conditions. Symptoms of both ADHD and autism can be managed with therapy and medication, although some people with autism might find therapy more beneficial while some people with ADHD might find medication more helpful.

Find out how our neurodiversity consultancy services can help employers support employees with autism and ADHD. You can also take our free ADHD test and autism test to find out if you have any traits of these neurodivergences.

Blog Author

April Slocombe