ADHD and Autism: Are They Related, and Can a Child Have Both?

Two Different Diagnoses, Not One Spectrum

Autism Spectrum Disorder and ADHD are defined by different core features. Autism features differences in social communication and restricted and/or repetitive patterns of behavior. Symptoms indicative of ADHD include limited attention span, impulse control, and/or hyperactivity. They are not two versions of the same underlying condition. Signs/symptoms of ASD present across a spectrum describing the needs and level of support required. 

Why They Get Confused So Often

The confusion is understandable, as the diagnoses can present with notable overlap of signs/symptoms. Symptom presentation can  involve difficulty with executive functions, social functioning, and emotional regulation. When a child meets diagnostic criteria for both ASD and ADHD, conditions together, difficulties may be more pronounced¹. A child who struggles to sit still, has trouble with transitions, or seems to tune out during conversations could be showing signs of ADHD, autism, or both, which is exactly why an evaluation matters more than guessing based on surface behavior.

Why It Took Until 2013 to Diagnose Both Together

For a long time, clinicians weren’t permitted to diagnose autism and ADHD in the same child at all. Earlier editions of the Diagnostic and Statistical Manual of Mental Disorders treated the two as mutually exclusive, meaning a child could receive one diagnosis or the other, but not both, regardless of what their actual symptom profile looked like². The DSM-5, published in 2013, changed this specifically, allowing clinicians to diagnose ADHD in the context of an autism diagnosis for the first time³. This single change had a significant effect on the research and clinical landscape, since it meant children who had always shown both symptom patterns could finally receive documentation and treatment reflecting their full picture.

How Common Is It for Both to Co-Occur?

Genuinely common. Research estimates that 50 to 70 percent of individuals diagnosed with autism also meet criteria for ADHD, and 15 to 25 percent of individuals diagnosed with ADHD also meet criteria for autism⁴. These are substantial numbers, not rare exceptions. A large school-population study specifically estimating combined diagnoses found the comorbid presentation itself, meeting full criteria for both conditions, at around 0.51 percent of children, with reported symptom overlap considerably higher than that, underscoring how much more common overlapping traits are than a formal dual diagnosis⁵.

• 50 to 70 percent of children with autism also meet criteria for ADHD
• 15 to 25 percent of children with ADHD also meet criteria for autism
• The DSM-5 (2013) was the first edition to allow both diagnoses in the same child
• Co-occurring ADHD and autism is often associated with greater functional impairment than either alone

Frequently Asked Questions

If my child has ADHD, does that mean they’re somewhere on the autism spectrum?

No. ADHD and autism are separate diagnoses with different core features. Having ADHD doesn’t place a child on the autism spectrum, though the two conditions frequently co-occur.

Can a child be diagnosed with both ADHD and autism at the same appointment?

Yes, when a comprehensive evaluation identifies criteria for both. This has only been formally permitted since the DSM-5 was published in 2013.

Why do ADHD and autism look so similar sometimes?

They share overlapping difficulties with executive function, social functioning, and emotional regulation, which can make the two conditions look alike on the surface even though their core features differ.

Does having both conditions mean more significant challenges?

Often yes. Research indicates that co-occurring ADHD and autism is associated with greater difficulty with executive function and social functioning compared with either condition alone.

How do clinicians tell the two apart during an evaluation?

A comprehensive evaluation assesses a child’s social communication profile, presence of repetitive behaviors, attention, and impulse control, rather than relying on any single behavior to make the distinction.

Getting a Full, Accurate Picture

ADHD and autism are related in how often they occur together, but they’re not the same condition, and only a comprehensive evaluation can tell you which one, or both, actually applies to your child.

If you have questions about autism diagnostic testing or how ADHD and autism might overlap for your child, we are here to help. 

Call us at 815-783-2544 or submit a contact form.

Know a parent wondering if ADHD and autism are the same thing? Share this with them. It might be exactly what they needed today.

Clinically verified by Dr. Eun-Yeop Lee, Ph.D., NCSP, BCBA, Westside Children’s Therapy

Where to Go Next

• Autism Diagnostic Testing at Westside Children’s Therapy
• Applied Behavior Analysis at Westside Children’s Therapy
• What to Do Right After an Autism Diagnosis

1. Frontiers in Psychiatry. Autism and ADHD in the DSM-5-TR era: an updated review
2. DSM-5 Changes in Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder: Implications for Comorbid Sleep Issues. PMC.
3. An update on the comorbidity of ADHD and ASD: a focus on clinical management. PubMed.
4. DSM-5 Changes in Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder: Implications for Comorbid Sleep Issues. PMC.
5. Canals J, et al. Prevalence of comorbidity of autism and ADHD and associated characteristics in school population: EPINED study. Autism Research, Wiley