Autism vs ADHD: Know the Differences

Autism vs ADHD

Although autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), sometimes referred to as ADD, share a number of similar symptoms that overlap, they are two very distinct neurodevelopmental disorders requiring accurate diagnosis and treatment. Unfortunately, a lack of understanding of the distinctions between ASD and ADD/ADHD and their shared symptoms too often lead to misdiagnosis, and/or a delayed diagnosis of one or the other. This can have a number of far-reaching negative impacts including greater severity of symptoms, additional mental and physical health issues, and a lower overall quality of life.

Unfortunately, a lack of understanding of the distinctions between autism and ADHD and their shared symptoms too often lead to misdiagnosis, and/or a delayed diagnosis of one or the other. Click To Tweet

What’s more, these two conditions can and often do occur together. While estimates vary, recently published research in Frontiers in Psychiatry states that 50-70% of individuals with ASD also have ADD/ADHD. And on the flip side, data from the Centers for Disease Control and Prevention (CDC) note that about 14% of children with ADD/ADHD also have autism diagnoses (though some estimates are much higher).

Research has found that untreated ASD and ADD/ADHD both have enough influence to cause significant behavioral, emotional, academic, and social problems in school, at home, and in life in general. Here’s what you need to know about their similarities and differences.


Autism and ADD/ADHD are both neurodevelopmental disorders that are more prevalent in boys.

Research has revealed that both disorders have a genetic component, meaning that they run in families Parents and siblings of individuals with ASD and ADD/ADHD are more likely to have the disorders themselves.

Since they stem from brain development issues, a number of areas controlled by the nervous system are affected in both conditions, such as movement, language, memory, social skills, and the ability to focus. Executive function is affected in both disorders as well, which accounts for issues with impulse control, decision-making, organization, concentration, and time management.


How autism and ADD/ADHD are characterized helps to define their differences. Let’s take a look at what makes each a distinct disorder.

Features of Autism Spectrum Disorder

ASD is primarily characterized by difficulty with social interactions, delayed communication, and restricted or repetitive behavior. Individuals with ASD may also have different ways of learning, moving, or paying attention. Early signs of autism may appear by age 2 or 3, or as early as one year with more severe developmental delays. The average age of diagnosis is around 4 years.

Children with ASD lack the ability to comprehend the social world intuitively. Common symptoms may include any of the following and more:

  • Deficits in social communication/interaction, especially non-verbal communication (e.g., missing social cues, failing to show or read facial expressions, failing to use hand gestures), and reciprocal communication; poor eye contact
  • Repetitive and restrictive behaviors such as rocking, pacing, or hand flapping; an intense focus on certain things; rigid adherence to routines; aversion to changes; sensory challenges (either under- or over-reactive to light, sound, taste, smell, touch)
  • Delay in speech, odd speech patterns; delayed motor skills; delayed cognitive or learning skills; hyperactive, impulsive, and/or inattentive behavior

In 2013, Autistic Disorder, Asperger’s Disorder, and Pervasive Developmental Disorder were combined into the ASD umbrella category, which is broken into three levels:

  • Level 1 – Requires some support (high-functioning autism)
  • Level 2 – Requires more support
  • Level 3 – Requires very substantial support throughout life

Features of ADD/ADHD

ADD/ADHD is a developmental disorder that is characterized by the following core symptoms:

  • Difficulty focusing and concentrating
  • Impulsivity (e.g., blurting out thoughts or exhibiting inappropriate behavior without thinking)
  • Short attention span for daily tasks (e.g., chores, homework, etc.)
  • Easily distracted
  • Procrastination
  • Disorganization
  • Lack of follow-through
  • Poor impulse control

Symptoms can range from mild to severe. The brain SPECT imaging work at Amen Clinics shows there are 7 types of ADD/ADHD, which share the core symptoms in addition to the following:

  • Classic – Restlessness, hyperactive, impulsive, fidgeting, and talking excessively
  • Inattentive – Difficulty maintaining focus, makes careless mistakes, appearing unmotivated, being sluggish, appearing preoccupied, not hyperactive
  • Overfocused – Excessive worrying, tendency to hold grudges, obsessive, may or may not be hyperactive
  • Temporal lobe – Irritability, periods of spaciness or confusion, feelings of fear or panic, dark thoughts, may or may not be hyperactive
  • Limbic – moodiness, feelings of hopelessness, loss of interest in things, chronic negativity, may or may not be hyperactive
  • Ring of Fire – overly sensitive, cyclic moodiness, oppositional, may or may not be hyperactive
  • Anxious – frequently nervous, stressed out, predicts the worst, conflict avoidant, may or may not be hyperactive

Kids may be diagnosed as young as age 4, according to American Academy of Pediatrics (AAP) guidelines, but more typically, between 8 and 10 years. ADD/ADHD has been described by experts as a disorder of self-regulation and executive function or trouble with the skills that help to manage everyday life.


Here’s where things get a little tricky with ASD and ADD/ADHD. Like so many brain disorders, autism, and ADD/ADHD are not just one thing. As explained, at Amen Clinics, brain SPECT imaging has helped identify 7 types of ADD/ADHD and has revealed there are 8-10 factors that can impact abnormal brain function in ASD. Also, in young children, symptoms can change as they grow and develop.

With so many variations of each disorder that can change over time, it’s not surprising that there are a number of shared or “overlap” symptoms between ASD and ADD/ADHD, which makes misdiagnosis or delayed diagnosis more likely. One research study identified the following traits as the most common overlap symptoms between the two disorders:

  • Impulsivity
  • Lack of focus (with ADHD, getting distracted by external activities; with autism, getting distracted by one’s own ideas and thoughts)
  • Speech delays
  • Difficulty organizing time, tasks, and projects (resulting from impaired executive function)
  • Difficulty with social interaction and making friends
  • Different ways of learning and learning disabilities
  • Sensory issues
  • Difficulty managing emotions such as anger and frustration

These shared symptoms make accurate diagnoses of both conditions more challenging. For example, distractibility and impulsivity—hallmarks of an ADD/ADHD diagnosis, often appear in people with ASD.

Also, individuals with ADD/ADHD often have speech delays, even though this is one of the identifying features of an ASD diagnosis. Children with ADD/ADHD often get distracted easily and can lose focus when they are speaking. Autistic children have major communication deficits.

Some research indicates that when there is first an ADD/ADHD diagnosis in a young child, it can mask symptoms of high-functioning autism or Asperger’s. This can lead to a misdiagnosis altogether or, on average, nearly a two-year (1.8 years) delayed diagnosis of ASD—that’s a combined figure of a 1.5-year delay in boys and a 2.6-year delay in girls.


As the figures above show, ADD/ADHD symptoms are very likely to be found in autistic individuals, and while ADD/ADHD individuals may also have autism, it is much less likely.

The reasons why ADD/ADHD and autism may co-occur aren’t clear. One theory suggests that these independent disorders occurring together may share a common underlying etiology. More research is needed.

What is clear though is that research shows that children with both ASD and ADD/ADHD are more likely to have more pronounced learning difficulties and impaired social skills than children who only have one of the disorders.


Co-occurrence is not to be taken lightly; both disorders require proper diagnosis, which should come from a qualified specialist, not a simple diagnostic test. Brain SPECT imaging can be helpful in understanding which type of these conditions is involved and assess any other underlying factors that may be factors.

Treatment for co-occurrence often starts with addressing ADD/ADHD symptoms and may include different types of therapy, such as behavioral, speech, social skills, and occupational therapies; neurofeedback; lifestyle changes; diet recommendations; nutritional supplements; and medication (when needed).

The sooner you start with personalized solutions targeted to your loved one’s brain, the sooner you can minimize symptoms. When both conditions are addressed properly, it can be life-changing, not only for the person with the disorders but also for their family and loved ones.

ADD/ADHD, autism spectrum disorder, and other mental health issues can’t wait. At Amen Clinics, we’re here for you. We offer in-clinic brain scanning and appointments, as well as mental telehealth, clinical evaluations, and therapy for adults, teens, children, and couples. Find out more by speaking to a specialist today at 888-288-9834 or visit our contact page here.


  1. Thank you for your work in identifying similarities in these disorders. I am 78 and as a child was taken to the Purdue University Psychology Department to be interviewed by a group of psychologists from around the country because I was always distracted while in school. I couldn't stay on task. At the time the recommendation was eye exercise. I was called a "Dreamer." I never did well in my studies throughout primary and secondary school. In my sophomore year, a teacher took interest in me and directed me to Debate and Speech competitions where I did very well. I believe this change taught me how to focus on a task and avoid dream interruptions. Later in college, I discovered that I am also dyslexic, making it difficult to read and comprehend. In my freshman year of college, I was afraid I would flunk out, so I learned to block out everything but study and made the Dean's List. With the fear gone, I returned to my natural ways and spread my focus across extracurricular activities such as debate, and student government, graduated, and had a successful career in information technology. In my 70's I found that I am having more difficulty controlling distractions, so my psychiatrist prescribed Adderall, which helps me stay focused. Since seeing Dr. Amen's TED Talks, I found BrainMD and added Neural Link, Brain Focus and Energy, and Smart Mushrooms to my morning routine. This has allowed me to cut my Adderall to 25% of the original dose. Children of this generation and adults are so fortunate to have access to the work Dr. Amen has done to focus on the neurological issue that causes what had been thought of as only psychiatric issues in the past.

    Comment by Steve Dolbow — April 14, 2023 @ 4:58 AM

  2. New research has revealed so many new facts and features about ADD and ASD. Does brain imaging reveal these disorders?

    Comment by Joyce Visnick — April 14, 2023 @ 6:44 AM

  3. When I started working as a School Psychologist at the elementary level, there were 2 children with Autism in the entire town. By the time I retired it was pretty much all I dealt with. I recognized that the majority of children also had ADHD but it was not treated for the most part because it was felt to be just another aspect of Autism at that time. I felt very strongly that those symptoms had the biggest impact on the students' ability to deal with their Autism symptoms. Those few students who were treated for ADHD were able to manage school so much better. Unfortunately, a number of their parents also had ADHD and would forget the meds, etc. Not an easy situation. At that time, Autism/Asperger's was romanticized as "super brilliant, quirky kids". Not from my experience…. I would not wish Autism on anyone!!

    Comment by Holly Matisis — April 14, 2023 @ 7:29 AM

  4. I am a subscriber and a follower. Recently, I have been asking myself if Dr. D. Amen,MD will ever address the subject of Asperger's, currently ASD. It has happened and, as a mother of an adult son who has been diagnosed and treated for other conditions and only later in life was told he has been misdiagnosed, and that he should be treated for ASD, I felt pain in my heart. Needless to say, I have been heartbroken. Hower, felt better when I have come across Dr. Kenneth Roberson's "Adult Asperger's Syndrome" Essential Guide in which he points that many ADHD symptoms overlap with Asperger's/ ASD, and that a person might have other mental health issues like bipolar.
    Dear Dr. Amen, thank you for the article and analysis. As I was reading, I have felt I was reading my son's story of struggle. It is only in recent years that children and adults who suffer from ASD started receiving help. It is easier to get treament for children, not so easy for adults.

    Comment by Irene Skibinski — April 14, 2023 @ 10:13 AM

  5. My son and I lives in Manila, Philippines
    Do you do consultation online?

    Comment by Grizel — April 14, 2023 @ 11:51 PM

  6. Would Amen clinics and/or SPECT be able to diagnose and help a speech difficulty similar to stuttering? Thanks!

    Comment by Julie Taylor — April 16, 2023 @ 11:13 PM

  7. Hello Julie, thank you for reaching out. We'd like to know more about your inquiry, please reach out to our Care Coordinators here:

    Comment by Amen Clinics — April 17, 2023 @ 9:18 AM

  8. Hello Grizel, thank you for reaching out. For more information about SPECT scans and consultations overseas, please contact our Care Coordinators:

    Comment by Amen Clinics — April 17, 2023 @ 9:52 AM

  9. I appreciate the research links in your article, that bring context and credibility to the post.

    Comment by Roger — May 21, 2023 @ 8:49 AM

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