Both autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) are conditions where the development of the brain has been affected in some way. This is known as a neurodevelopment disorder.
This means that both ASD and ADHD affect the central nervous system, potentially impacting social and focusing skills, language, movement, and memory. Much research has established that the two conditions typically coexist in patients, but there is no conclusive evidence to suggest why this is.
ADHD vs. Autism
ADHD & Autism: Similarities
One of the connections between the two conditions is that both have been linked to genetic causes, so they tend to run in families. Some similarities between ASD and ADHD include the following:
- Hyperfocus (extreme focus only on topics or things of interest, to the exclusion of other topics or things)
- Impulsive behavior
- Inability to sit down for long periods (including but not limited to physical fidgeting)
ASD and ADHD affect the brain’s executive functioning, which governs focus and organization, time management, decision making, and impulse control. This means that many children who grow up with either ASD or ADHD — or both — struggle with understanding and acting on social skills. ASD and ADHD more often occur in boys than girls.
Such are the similarities between the two conditions that researchers published in the Journal of Attention Disorders noted that “the two disorders may be a continuum and have a common origin.”
ADHD & ASD: Differences
So intertwined is the relationship between ASD and ADHD that some have wondered if ADHD is itself an expression of autism. While it is clear that this is not the case, the close overlap between the two conditions, as well as public misunderstandings of their symptoms, gives rise to such misconceptions. ADHD and ASD are both neurodevelopmental disorders, the causes of which are not fully understood.
But for all the similarities between attention-deficit hyperactivity disorder and autism spectrum disorder, key differences make both conditions distinct.
For example, children who have ADHD typically struggle to pay attention to one subject and tend to get distracted quite easily. Children with autism may develop hyperfocus on one subject or object and will not focus on things of no interest.
An easy way to spot the difference between the two is when children do their homework. A child who has ADHD will likely not be able to concentrate on their assigned subject, even if it is a favorite. A child with autism will have an obsessive level of concentration on their favorite subject but will be unable to engage in subjects they are not interested in.
Communication Differences in ADHD & Autism
Because of the neurodevelopmental nature of both conditions, communication is also affected but in different ways. Children with ADHD will likely:
- Talk without pausing or ceasing.
- Be active and animated when talking, sometimes disruptively so.
- Not notice when they are disturbing others.
- Interrupt others.
- Try to have the (literal) last word in every conversation.
But while autistic children are equally neurodivergent, their condition affects their communication abilities differently. Children with autism will likely:
- Struggle to express themselves, specifically when describing their feelings.
- Not use gestures or body language when communicating.
- Not make eye contact.
- Not understand when to let another person speak.
- Not respond to conversation cues or prompts offered by others.
Responding to Changes in Environment
Children with ADHD tend to become quickly bored with routines and structures that don’t excite them. They typically require variety and diversity in their education and upbringing to maintain focus and attention.
Children with autism, however, do not respond well to unexpected changes and alterations to their schedules. Many children with ASD require intensely structured and established routines, and such a format might be the only way they feel comfortable in an academic or home setting.
Examples include consuming the same media or eating the same thing for dinner. A child with ADHD might become bored, distracted, or frustrated with a book or a TV show after just a few minutes or might want something else to eat after just a couple of bites.
When ADHD & ASD Occur Together
Although the two conditions are distinct, they often occur together, resulting in confusion and consternation. Almost 3 in 10 young children who have autism also show signs of ADHD, which is three times higher than for children in the general population.
Researchers published in the Autism journal noted that it isn’t surprising that whatever might cause autism to develop in the brain could conceivably “also cause a second developmental outcome,” such as ADHD.
Past research has also theorized that autism and ADHD are “two independent disorders” that occur together through a third independent factor. What that factor might be is an ongoing question, but the most supported school of thought is that a genetic component is at play.
Several genetic studies have supported the theory that both ADHD and ASD have their origins in familial factors. The researchers who have examined this perspective suggest that shared genetic and neurobiological factors suggest why ADHD and ASD can occur with such frequency within the same family — and the same patient.
Treating Co-Occurring ASD & ADHD
When a child has both disorders, the diagnosis can seem incredibly difficult for parents to handle. Fortunately, there are strategies for parents and caregivers to help their child successfully (and fruitfully) manage their conditions.
The first step is to partner with school counselors so parents can mirror the counselors’ evidence-based interventions (behavioral techniques that work for kids who have both distinct and co-occurring conditions) at home. Such practices will likely address required organizational skills at school and home and can be scaled as the child grows.
You’ll also want to find external support for your child, depending on their needs. Applied behavioral analysis (ABA) therapy can be helpful for both ASD and ADHD. Individual therapy, medication management, and family or group therapy may also benefit your child. Elemy offers in-home ABA therapy and virtual 1:1 therapy and family therapy to support both conditions.
Strategies for Parents
Parents should work with their child’s school counselor, pediatrician, therapists, and other caregivers to develop strategies to apply at home consistently. This can be as simple as providing positive reinforcement and feedback or establishing and maintaining day-to-day structure and routines that fit your family.
It may include creating visual lists, rules, and schedules, and then putting them up everywhere for the child to see and for the parents to follow.
For children who have both ADHD and ASD, managing the co-occurring conditions involves a great deal of “parent training,” where counselors and therapists teach parents strategies to manage the often unpredictable and unintuitive behaviors of their children.
Since children with one or both of these conditions may struggle with social skills, parent training helps with understanding how these conditions hinder standard development. This is vital for parents to know because typical lessons about etiquette may not work and may further delay social and communication development.
The Co-Occurrence of Autism and Attention Deficit Hyperactivity Disorder in Children — What Do We Know? (April 2014). Frontiers in Human Neuroscience.
Are ASD and ADHD a Continuum? A Comparison of Pathophysiological Similarities Between the Disorders. (September 2015). Journal of Attention Disorders.
Examining Autistic Traits in Children With ADHD: Does the Autism Spectrum Extend to ADHD? (September 2011). Journal of Autism and Developmental Disorders.
The Evolution of ADHD: A Disorder of Communication? (March 2000). The Quarterly Review of Biology.
Overlaps and Distinctions Between Attention Deficit/Hyperactivity Disorder and Autism Spectrum Disorder in Young Adulthood: Systematic Review and Guiding Framework for EEG-imaging Research. (January 2019). Neuroscience and Biobehavioral Reviews.
A Review on Cognitive and Brain Endophenotypes That May Be Common in Autism Spectrum Disorder and Attention-deficit/hyperactivity Disorder and Facilitate the Search for Pleiotropic Genes. (May 2011). Neuroscience and Biobehavioral Reviews.
Exploring the Relationship Between Autistic-like Traits and ADHD Behaviors in Early Childhood: Findings From a Community Twin Study of 2-Year-Olds. (February 2010). Journal of Abnormal Child Psychology.
Treatment for Co-Occurring Attention Deficit/Hyperactivity Disorder and Autism Spectrum Disorder. (July 2012). Neurotherapeutics.
The Effectiveness of Parent Training for Children With Autism Spectrum Disorder: A Systematic Review and Meta-analyses. (December 2020.) BMC Psychiatry.