ADHD Vs Autism: Differences, Similarities, Causes & Treatment 2023

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Medically reviewed by Kimberly Langdon, MD

adhd vs autism

Attention deficit hyperactivity disorder (ADHD) is a lifelong condition that affects behavior and is commonly diagnosed in children. Similarly, autism is a complex chronic disorder frequently appearing during childhood, affecting behavior and development.

Although ADHD and autism are distinct mental health conditions that affect brain neurodevelopment, they can co-exist, showing similar symptoms and are sometimes mistaken for each other. 

Approximately 5% of the population worldwide[1] is reported to have ADHD. Studies estimate that two-thirds of these also have autistic features[2] and one-fifth co-diagnosed[3] with Autism spectrum disorder (ASD). In contrast, up to half of autistic individuals also thought to exhibit ADHD symptoms[4].

There is a great deal of research on ADHD and autism independently, but there has been less understanding of how and why both conditions frequently occur together or show similar symptoms. 

What’s the Relationship Between ADHD & Autism?

Autism usually falls under the umbrella term Autistic spectrum disorder (ASD). Both ADHD and ASD are neurodevelopmental disorders, affecting brain development and the central nervous system, responsible for movement, language, memory, social and focusing skills.

Although both conditions can affect adults, diagnosis is most common during childhood. According to the CDC, 1 in 10 children[5] aged between 5 and 17 years is diagnosed with ADHD, making it one of the most common childhood neurodevelopmental conditions in the U.S. Of these children with ADHD, 14%[5] also suffer from ASD.

Studies show ADHD and ASD can occur together[2] simultaneously, making it difficult to distinguish between the two. Not every child is diagnosed clearly with either ADHD or ASD or both. 

Comparing ADHD Vs Autism

ADHD is most evident during childhood when it is easier to spot initial signs like the inability to conform to conventional behavior at school. Children with ADHD can disrupt the classroom environment, making it difficult for them and others to learn. 

Kids with ADHD can show extreme levels of inattention, hyperactivity and impulsive behaviors. They may have difficulty sitting still or find trouble focusing their attention on particular tasks.

There are three main types of ADHD with particular dominance in either one kind or the other, or a combination of both. The inattentive type is easily distracted and disorganized, while the hyperactive type constantly moves, fidgets, or talks. 

Although a mixture of both types is typical, hyperactivity[6] is the most common single ADHD symptom seen in preschool-age children. 

ASD is a group of complex conditions in which autistic individuals vary in how they see, hear and feel the world around them. About 1 in 68 children in the U.S.[7] are diagnosed with ASD.

Like everyone, those with autism have their own merits and shortcomings but are often seen by the outside world as physically and emotionally distant, socially awkward, and unable to communicate effectively. 

Similarities between ADHD and ASD

Since both ADHD and ASD can affect language, movement, concentration, and social skills, they may share similar features. 

Sharing features during the early stages

In the early stages[2], particularly in children, both conditions’ symptoms can be alike and sometimes easily mistaken for each other. On occasion, some children cannot be clearly diagnosed as having one state and not the other or misdiagnosed with each other, but ADHD and ASD are two distinct conditions. 

Difficulty processing information

Not only individuals with ADHD may have difficulty organizing their thoughts and ability to learn new information, but those with ASD may also take longer[2] to process new data with much less accuracy than those without either condition. 

Inability to stay still

ADHD sufferers are often hyperactive, fidget and have trouble sitting still. Similarly, those with ASD may sometimes display specific movements that comfort them, such as rocking back and forth or twiddling fingers. To some, these self-comforting ASD behaviors[2] may be seen as an inability to keep still. 

Difficulty following instructions

Teachers may comment that children with ADHD or ASD don’t seem to listen as both may have trouble following directions or focusing on individual tasks, disrupting learning. 

Have trouble relating to others

Those with ADHD and ASD may seem to be cold or can’t relate to other people’s emotions or feelings, making it challenging to maintain relationships with others. 

Diagnosis favoring boys

Studies show that boys are more than twice as likely[5] to be diagnosed with ADHD than girls. Similarly, boys are also more likely[7] to have ASD than girls. They also reveal that boys with ADHD tend to be more hyperactive, while girls can be more quietly inattentive, like daydreaming or hyper talkative. 

Because ADHD and ASD symptoms present differently[5] in boys and girls, this may explain why more boys are diagnosed than girls, simply because hyperactivity is a more easily recognizable sign of ADHD. 

Differences Between ADHD and ASD

Despite both conditions sharing similar symptoms, they are two different disorders.

Ability to focus 

While those with autism may lose concentration when doing tasks they don’t particularly like, they can show intense focus[7] and fixate on special interests they have. Those with ADHD are easily distracted and generally dislike any task that requires attention to detail. 


Autistic individuals tend to be socially awkward with the inability to put thoughts and feelings together to communicate effectively and rarely make eye contact. Though on occasion[7], some with ASD can talk to great lengths but only about their particular interests.

In contrast, those with ADHD may have the ‘gift of the gab’, disrupting others mid-conversation and leading their own confidently. 


Individuals with ASD generally prefer order, doing the same things repeatedly[7] and dislike unpredictable changes. They find comfort in having the same daily routine, eating the same food or being severely attached to only one particular favorite toy. In comparison, those with ADHD can be disorganized, dislike repetition[1] and often get bored fairly quickly.


Although research on the comorbidity of ADHD and ASD has increased over recent years, there is still much to learn about connecting the two conditions. Studies show genetics[8] possibly plays an essential role in the origins of both disorders.

Many studies further support this, revealing that family members[9] of individuals suffering from either ADHD or ASD frequently display symptoms of the other condition.


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A diagnosis of either ADHD or ASD doesn’t depend on a strict set of conditions or observations. Instead, doctors often ask for feedback and input from parents, teachers or other carers to look for patterns of behaviors over time. 

Both diagnoses are most likely done during childhood and often involve questionnaires, surveys, interviews and observations. 


Starting proper ADHD and ASD treatment depends on receiving a correct diagnosis. 

Because of the complexity and similarities between the two conditions, parents may opt to see a specialist in child behavior disorders over general pediatricians or medical practitioners. 

Behavioral Therapy

Behavioral therapy is a broad term for different therapy types to treat mental health disorders by identifying and changing unhealthy or self-destructive behaviors. These don’t change symptoms but teach the individual how to cope with and control their thoughts and actions. 

Younger children with ADHD may start with behavioral therapy; older kids will typically combine therapy with medication. 

No cure exists for those with ASD, but there are many ways to help relieve symptoms and provide support to make life easier, such as speech therapy[10] to aid communication. 


While those with ADHD symptoms respond well to medications like methylphenidate and amphetamine, they are generally less effective on ASD symptoms. Equally, autistic individuals with ADHD symptoms may find relief[11] from such medicines.

Because of the increase in the co-occurrence of those with ADHD and ASD, research has increased in trialing medication specifically to treat ASD symptoms. However, only a small number of medicines are formally approved to treat those with ASD and mainly only for treating irritability[12]


  • Both ADHD and ASD are neurodevelopmental conditions that can impact emotions, behaviors, and the ability to learn and process new information. 
  • They are lifelong conditions that commonly co-exist with each other and are frequently diagnosed during childhood. 
  • Similar features of both conditions sometimes lead to confusion over their diagnosis, but ADHD and ASD are distinct disorders with differences.
  • Genetics may play a role in the comorbidity of ADHD and ASD, but more research is needed to understand this fully. 
  • ADHD and ASD can both be managed with correct therapy and treatment adapted to each individual.

+ 12 sources

Health Canal avoids using tertiary references. We have strict sourcing guidelines and rely on peer-reviewed studies, academic researches from medical associations and institutions. To ensure the accuracy of articles in Health Canal, you can read more about the editorial process here

  1. Polanczyk, G., de Lima, M.S., Horta, B.L., Biederman, J. and Rohde, L.A. (2007). The Worldwide Prevalence of ADHD: A Systematic Review and Metaregression Analysis. American Journal of Psychiatry, [online] 164(6), pp.942–948. Available at:
  2. ‌Mulligan, A., Anney, R.J.L., O’Regan, M., Chen, W., Butler, L., Fitzgerald, M., Buitelaar, J., Steinhausen, H.-C., Rothenberger, A., Minderaa, R., Nijmeijer, J., Hoekstra, P.J., Oades, R.D., Roeyers, H., Buschgens, C., Christiansen, H., Franke, B., Gabriels, I., Hartman, C. and Kuntsi, J. (2008). Autism symptoms in Attention-Deficit/Hyperactivity Disorder: A Familial trait which Correlates with Conduct, Oppositional Defiant, Language and Motor Disorders. Journal of Autism and Developmental Disorders, [online] 39(2), pp.197–209. Available at:
  3. ‌Price, A., Newlove-Delgado, T., Eke, H., Paul, M., Young, S., Ford, T. and Janssens, A. (2019). In transition with ADHD: the role of information, in facilitating or impeding young people’s transition into adult services. BMC Psychiatry, [online] 19(1). Available at:
  4. ‌Lee, D.O. and Ousley, O.Y. (2006). Attention-Deficit Hyperactivity Disorder Symptoms in a Clinic Sample of Children and Adolescents with Pervasive Developmental Disorders. Journal of Child and Adolescent Psychopharmacology, [online] 16(6), pp.737–746. Available at:
  5. ‌Anon, (2021). FastStats – Attention Deficit Hyperactivity Disorder. [online] Available at:
  6. CDC (2020). Data and Statistics About ADHD. [online] Centers for Disease Control and Prevention. Available at:
  7. ‌ (2021). NIMH» Attention-Deficit/Hyperactivity Disorder. [online] Available at:
  8. ‌Prevalence of autism spectrum disorder among children aged 8 years – autism and developmental disabilities monitoring network, 11 sites, United States, 2010. (2014). Morbidity and mortality weekly report. Surveillance summaries (Washington, D.C. : 2002), [online] 63(2). Available at:
  9. ‌Franke, B., Neale, B.M. and Faraone, S.V. (2009). Genome-wide association studies in ADHD. Human Genetics, [online] 126(1), pp.13–50. Available at:
  10. ‌Nijmeijer, J.S., Hoekstra, P.J., Minderaa, R.B., Buitelaar, J.K., Altink, M.E., Buschgens, C.J.M., Fliers, E.A., Rommelse, N.N.J., Sergeant, J.A. and Hartman, C.A. (2008). PDD Symptoms in ADHD, an Independent Familial Trait? Journal of Abnormal Child Psychology, [online] 37(3), pp.443–453. Available at:
  11. ‌CHADD (2019). ADHD and Autism Spectrum Disorder – CHADD. [online] CHADD. Available at:
  12. Davis, N.O. and Kollins, S.H. (2012). Treatment for Co-Occurring Attention Deficit/Hyperactivity Disorder and Autism Spectrum Disorder. Neurotherapeutics, [online] 9(3), pp.518–530. Available at:

Medically reviewed by:

Kimberly Langdon

Christina Cheung holds a Master’s of Pharmacy from the University of Bath (UK) and is a freelance writer specializing in medicine and science. With over a decade of experience as a community and hospital pharmacist both in the UK and abroad, she has dealt first-hand with patients facing medical difficulties and decisions. She now writes to promote medical health and wellness to better the community. Christina also has a published science blog with a passion for inspiring and encouraging medicine and science for kids and students. While not writing, she can be found strolling through the country parks with her family and pet dog.

Medically reviewed by:

Kimberly Langdon

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