When your child receives an unwanted diagnosis (or is in need of medical intervention for troubling delays for the first time), it can be unnerving to say the least. You may find yourself questioning everything you’ve been told and wondering if there is another possible cause for your child’s behaviors and symptoms.

While medical misdiagnoses are not a regular occurrence, they are becoming more common, especially in the case of conditions like Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD).

Can ADHD be mistaken for ASD? In short, yes; due to many condition similarities and symptom overlaps, the two are known for diagnosis confusion. We’ll touch on this further. It is important to determine if your child is receiving the correct interventions and treatment for their specific disorder, which may require ample research and conversation with your medical team.

What do parents need to know about the similarities, differences and diagnostic criteria of ADHD and Autism Spectrum Disorder? Keep reading to find out.

*This article does not include preventative tips or recommendations for the conditions thereby mentioned. Please do not use this information to diagnose your self or loved ones. If you have any questions or concerns regarding your child’s symptoms or medical condition, consult your pediatrician.

Diagnostic Criteria

While Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder are both common neurodevelopmental disorders most often found in children, ADHD is the more common diagnosis.


According to the CDC, 6.1 million children (as of 2016) have been diagnosed with ADHD. This makes up 9.4% of the population ages 2-17 years. Three-fourths of children are 9 years of age and younger when diagnosed, and one-third are given a diagnosis by age 6.

The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition) gives the following criteria for an ADHD diagnosis:

1. Inattention (5-6 of the following, with inappropriate displays for current developmental level):

  • Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or with other activities.
  • Often has trouble holding attention on tasks or play activities.
  • Often does not seem to listen when spoken to directly.
  • Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., loses focus, side-tracked).
  • Often has trouble organizing tasks and activities.
  • Often avoids, dislikes, or is reluctant to do tasks that require mental effort over a long period of time (such as schoolwork or homework).
  • Often loses things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).
  • Is often easily distracted.
  • Is often forgetful in daily activities.

2. Hyperactivity and Impulsivity (5-6 of the following, disruptive and inappropriate behavior for the person’s development):

  • Often fidgets with or taps hands or feet, or squirms in seat.
  • Often leaves seat in situations when remaining seated is expected.
  • Often runs about or climbs in situations where it is not appropriate (adolescents or adults may be limited to feeling restless).
  • Often unable to play or take part in leisure activities quietly.
  • Is often “on the go” acting as if “driven by a motor”.
  • Often talks excessively.
  • Often blurts out an answer before a question has been completed.
  • Often has trouble waiting their turn.
  • Often interrupts or intrudes on others (e.g., butts into conversations or games).

3. In addition to the above criteria, the following conditions must be met:

  1. Several symptoms were present before the age of 12 years.
  2. Several symptoms are present in multiple settings (such as school, home, with friends or relatives, in other activities, etc).
  3. There is clear evidence that symptoms interfere with daily functioning.
  4. The symptoms cannot be explained by another mental disorder.

While parents and caregivers are able to observe and confirm the conditions aforementioned, an official diagnosis can only be given by a medical professional (primary care doctor, psychologist, or psychiatrist).

Many parents find it helpful to request and include anecdotal evidence given by adults present in other spheres of the child’s life, such as: coaches, teachers, therapists, babysitters, etc.


Diagnosing ASD is difficult for many of the same reasons that establishing a conclusive ADHD diagnosis is: there is no clear-cut medical test (like a blood test) to determine validity at this time. ASD is diagnosed via a behavioral/developmental screening.

Unlike ADHD, ASD can be detected as early as 18 months old or younger, according to the CDC. Early signs include:

  • Avoiding eye contact.
  • Having little interest in other children or caretakers.
  • Limited display of language (for example, having fewer words than peers or difficulty with use of words for communication).
  • Getting upset by minor changes in routine.

The most important factors for diagnosing a child with Autism Spectrum Disorder are what medical professionals refer to as Developmental Monitoring, Screening and Evaluating.

  1. Developmental Monitoring: involves observations of a child’s growth by present adults (parents, medical staff, grandparents, early childhood providers, and other caregivers) to determine if important milestones are being met. You can reference any number of milestone checklists for this monitoring process.
  1. Developmental Screening: a more formal way of tracking a child’s development, involving questionnaires and tools provided by a healthcare provider. This level of observation is normally performed by a doctor or qualified nurse and is completed less often than monitoring, as described above.

The American Academy of Pediatrics (AAP) recommends screening for children at well-child visits at the following ages: 9 months, 18 months (for ASD specifically), 24 months (for ASD specifically), and 30 months. Additional screening may be necessary for children who are at higher risk of developing ASD.

Diagnostic Instruments include, but are not limited to:

  • Autism Diagnostic Interview-Revised (ADI-R): utilizes parental interview for assessment.
  • Autism Diagnostic Observation Schedule (ADOS): uses observation and interaction with the child.
  • The Childhood Autism Rating Scale (CARS): assesses the severity of autism based on observation of the child.

Signs and Symptoms of Autism Spectrum Disorder include:

1. Social Skill Delays

  • Does not respond to name by 12 months of age
  • Avoids eye-contact
  • Prefers to play alone
  • Does not share interests with others
  • Only interacts to achieve a desired goal
  • Has flat or inappropriate facial expressions
  • Does not understand personal space boundaries
  • Avoids or resists physical contact
  • Is not comforted by others during distress
  • Has trouble understanding other people’s feelings or talking about their own feelings

2. Communication Issues

  • Delayed speech and language skills
  • Repeats words or phrases over and over (echolalia)
  • Reverses pronouns (e.g., says “you” instead of “I”)
  • Gives unrelated answers to questions
  • Does not point or respond to pointing
  • Uses few or no gestures (e.g., does not wave goodbye)
  • Talks in a flat, “robot-like,” or sing-song voice
  • Does not pretend in play (e.g., does not pretend to “feed” a doll)
  • Does not understand jokes, sarcasm, or teasing

3. Other Symptoms include:

  • Sensory issues: sensitivity to light, noise, touch, pain, smell, or taste
  • Repetitive behaviors
  • Self-injury
  • Atypical eating behavior
  • Sleep problems
  • Overfocused: unable to shift attention between tasks

For parents questioning their child’s diagnosis or seeking to pursue medical intervention for the first time: begin by taking meticulous notes of any of the above symptoms, in congruence with tracking developmental milestones as a means of monitoring, as previously described. Then, follow up with a team of trusted medical professionals for further diagnostic confirmation or redirection.

Similarities and Comorbidity

Thanks to recent attention given to the relationship between and comorbidity of Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder, a myriad of scientific studies and scholarly articles are available today to discuss the similarities between the two diagnoses. One such study begins its discussion by confirming that 50% of children with ASD suffer from three characteristics common to ADHD:

  • Hyperactivity
  • Inattention
  • Impulsivity

Yet another study confirms that children with ADHD and ASD showcase a substantial overlap in functional brain connectivity, suggesting the two diagnoses share a similar level of abnormal neurodevelopment compared to neurotypical individuals. In short, it appears as though the ADHD brain and the ASD brain function similarly, though the two disorders’ behavior and cognition manifest differently.

Other Similarities Between ADHD and ASD:

It’s no wonder that ADHD can be mistaken for autism, and vice versa!

Percentage of children with ADHD and another disorder:

Image Source: Centers for Disease Control and Prevention


According to the CDC, 6 in 10 children with ADHD have at least one other mental, emotional, or behavioral disorder. 14% of children diagnosed with ADHD have also been diagnosed with Autism Spectrum Disorder. If this is true for your child, you will likely need (or already have) a highly specialized and unique treatment plan.

What Does It All Mean?

Since ample research suggests overlap between the two disorders, medical professionals agree that accurate, distinct diagnoses are of the utmost importance. An article published by the American Academy of Pediatrics revealed that in a study of almost 1,500 children (ages 2-17 years) diagnosed with Autism Spectrum Disorder, approximately 20% of them were initially diagnosed with Attention Deficit Hyperactivity Disorder, years prior to their ASD diagnosis.

Autism looks so similar to ADHD that many children are misdiagnosed and require later corrective action to the diagnosis. This finding is significant because while much is unknown about ASD, it is conclusive that early diagnosis and treatment lead to better outcomes for autistic children.

At this point, you might be feeling a little overwhelmed (and maybe even confused). Don’t panic. Your child’s diagnosis is a big deal, but you don’t have to figure it out by yourself. With the help of informed pediatric care and a supportive medical team, your family can benefit from an early, accurate diagnosis of your child’s ADHD or ASD symptoms.

Evergreen Home Healthcare supports parents, caregivers, and their special needs children in a myriad of capacities. If you find yourself navigating a disorder misdiagnosis or needing a team of compassionate, competent healthcare professionals, Evergreen is proud to offer a wide array of pediatric services, including: Parent CNA Program, In-Home Support Services, Private Duty Nursing, Staffed CNA Care, and Skilled Nursing.

Reach out to Colorado’s top pediatric home healthcare agency today!