Autism and ADHD Comorbidity: How Common It Is, How It's Diagnosed, and What Helps

Yes, autism and ADHD often occur together. In a 2016 to 2018 U.S. parent survey, about 44% of autistic children also had ADHD, and CDC 2022 survey data show about 14% of children with ADHD also have autism. Since DSM-5 in 2013, clinicians can diagnose both in the same child.

How Common Is It for Autism and ADHD to Occur Together?

Estimates vary because studies differ in who they include and how ADHD is identified. Two large reviews put ADHD at roughly 28% to 39% of autistic people: 28% across 96 studies in The Lancet Psychiatry, and 38.5% in a later meta-analysis. A U.S. parent survey covering 2016 to 2018 found that 43.8% of children with autism also had ADHD. Higher figures, such as 50% to 70%, usually come from individual clinic-based samples, which tend to run higher than population-based estimates.

The reverse overlap is smaller. CDC survey data from 2022 show that about 1 in 7 children with ADHD (14.4%) also had autism.

Autism vs. ADHD: What Sets Them Apart

A meta-analysis of executive-function studies found that children with both conditions look more like children with ADHD alone, and have more difficulty than children with autism alone. If restlessness is your main concern, see our post on does autism cause hyperactivity.

What Autism and ADHD Can Look Like Together

When a child has both, the signs rarely arrive in neat categories. The CDC describes three ADHD presentations: predominantly inattentive, predominantly hyperactive-impulsive, and combined. Autistic traits can sit on top of any of them, so one behavior can have more than one explanation.

These are patterns families describe, not a checklist, and only a qualified evaluator can say which explanation fits your child. Picture changes with age, too: the CDC notes that ADHD symptoms in adults "may look different" from those in children.

Routines are a common trouble spot. A token system for routines can make each step visible and give a child with attention differences something to work toward.

How a Dual Diagnosis Works

Before 2013, the DSM-IV said ADHD couldn't be diagnosed if its symptoms occurred only during the course of a pervasive developmental disorder such as autism. The DSM-5 removed that exclusion, so both diagnoses are now allowed. Each still has to meet its own criteria.

Timing matters. In a U.S. parent-survey study, children diagnosed with ADHD before autism received their autism diagnosis about 3 years later than children whose ADHD was diagnosed at the same time or afterward. A later study found a delay of about 1.8 years in children and adolescents. Attention and hyperactivity can overshadow autism traits, though findings vary between studies.

Two practical takeaways:

• If a child with ADHD also has persistent differences in social communication, intense routines or interests, or sensory distress, it's reasonable to ask the clinician about an autism evaluation. Our guide to ADOS testing explains what one involves.
• If an autistic child's attention or hyperactivity is getting in the way at home or school, ask about an ADHD assessment.

A developmental-behavioral pediatrician, child psychologist or child psychiatrist can evaluate for both. ABA providers such as BCBAs don't diagnose.

What Does the Research Say Helps?

Research on children who have both conditions is smaller than research on either alone, so it's worth being specific about what is known.

The best-known trial is a 2015 study of 128 children ages 5 to 14 with both autism and ADHD. Researchers compared the medication atomoxetine, a structured behavioral parent-training program, both together, and placebo. ADHD symptoms improved more than with placebo in all three active groups. Medication produced the larger gains, parent training alone also helped, and the combination wasn't clearly better than medication alone over the 10-week trial. Medication also reduced noncompliance.

Two cautions. Response rates to ADHD medications are generally lower in autistic children than in children with ADHD alone, and side effects can differ, so medication decisions belong with a prescribing clinician. And parent training in that trial was a specific, structured program, not a stand-in for every parent-coaching approach.

Where ABA Fits (and Where It Doesn't)

When a family and clinician decide ABA belongs in the plan, a BCBA can build supports that serve attention and autism-related needs at once. Examples include a visual schedule so the next step is easy to see, a first-then board for transitions, short task steps with reinforcement for finishing each one, and planned movement breaks. These are examples of what a BCBA can design, not treatments shown to work for ADHD in the studies above. The BCBA designs and oversees the plan, and RBTs deliver sessions under that supervision.

At Apex ABA, we start with a BCBA-led assessment of your child's skills, strengths and daily routines, then build a plan that fits what your child's pediatrician, psychologist and teachers are already doing. We serve children ages 2 to 12 across North Carolina, Georgia and Maryland through in-home ABA therapy. If your child has both diagnoses, or you're not sure yet, talk with our team and bring any evaluation reports you have.

Getting School Support: 504 Plan or IEP?

Children with both conditions can qualify for school supports under two federal laws. An IEP, under IDEA, provides specialized instruction, related services and measurable goals. A 504 plan, under Section 504, provides accommodations so a student can access the regular curriculum.

CHADD notes that ADHD usually falls under IDEA's "Other Health Impairment" category, and that IDEA requires a need for special education while Section 504 requires a substantial limit on a major life activity. Which plan fits depends on how much specialized instruction your child needs, not on the diagnosis alone. Our guide to 504 plan vs. IEP walks through the choice and the timing.

The hardest parts of the school day are often the least structured ones. See cafeteria and lunchroom sensory challenges, how recess and unstructured time differ from the classroom, and classroom strategies that help both attention and sensory needs.

Frequently Asked Questions

Q: Is AuDHD an official diagnosis?

A: No. "AuDHD" is an informal term for having both autism and ADHD. Clinicians diagnose each condition separately. Our guide to AuDHD vs. ADHD vs. autism explains how the profiles overlap and differ.

Q: Do ADHD medications treat autism too?

A: No. ADHD medications target attention, hyperactivity and impulsivity, not the core features of autism. They may help some autistic children with ADHD symptoms, and your prescriber can explain what to expect.

Q: Are girls diagnosed later than boys?

A: In one study of people who received an ADHD diagnosis first, the autism diagnosis came 2.6 years later for girls and 1.5 years later for boys. If your daughter has an ADHD diagnosis but social or sensory difficulties persist, it's worth raising an autism evaluation.

Q: Is fidgeting or stimming a sign of autism, ADHD or both?

A: It can be either, or neither. The movement can look identical, so clinicians look at why it happens and what else is present. See ADHD stimming vs. autism stimming for the differences.

Q: Which should we address first, autism or ADHD?

A: There's no fixed order. Clinicians usually prioritize whatever is most affecting safety, learning and daily life right now, and the research trial above treated both together. Ask your care team to explain their priorities.

Q: Can an adult have both autism and ADHD?

A: Yes. DSM-5 allows both diagnoses in the same person at any age, and the CDC notes that ADHD in adults may look different from ADHD in children. Many adults are first assessed for one condition and later learn about the other. A psychologist or psychiatrist who evaluates both can sort out which traits belong to which. If you are an adult exploring this, contact Apex ABA and we can point you to the right kind of evaluator. We provide ABA therapy for children, so evaluation and care for adults happen elsewhere.

Sources

• American Psychiatric Association, Highlights of Changes from DSM-IV-TR to DSM-5 (comorbid ASD and ADHD diagnosis now allowed) — https://www.psychiatry.org/File%20Library/Psychiatrists/Practice/DSM/APA_DSM_Changes_from_DSM-IV-TR_-to_DSM-5.pdf
• American Psychiatric Association, DSM-5 ADHD fact sheet — https://www.psychiatry.org/File%20Library/Psychiatrists/Practice/DSM/APA_DSM-5-ADHD.pdf
• Lai et al., Prevalence of Co-Occurring Mental Health Diagnoses in the Autism Population, The Lancet Psychiatry (2019) — https://discovery.ucl.ac.uk/10081954/
• Prevalence of Attention-Deficit/Hyperactivity Disorder in Individuals with Autism Spectrum Disorder: A Meta-Analysis — https://www.sciencedirect.com/science/article/pii/S1750946721000349
• Prevalence and Treatment of Mental, Behavioral, and Developmental Disorders in Children with Co-Occurring ASD and ADHD: A Population-Based Study, PMC — https://pmc.ncbi.nlm.nih.gov/articles/PMC10160807/
• CDC, ADHD Prevalence Among U.S. Children and Adolescents (2022 National Survey of Children's Health) — https://stacks.cdc.gov/view/cdc/160350/cdc_160350_DS1.pdf
• Miodovnik et al., Timing of the Diagnosis of ADHD and Autism Spectrum Disorder, Pediatrics (2015) — https://pubmed.ncbi.nlm.nih.gov/26371198/
• Kentrou et al., Delayed Autism Spectrum Disorder Recognition in Children and Adolescents Previously Diagnosed with ADHD, Autism (2019) — https://doi.org/10.1177/1362361318785171
• Handen et al., Atomoxetine, Parent Training, and Their Combination in Children with ASD and ADHD, JAACAP (2015) — https://pubmed.ncbi.nlm.nih.gov/26506581/
• Comparing Executive Functions in Children and Adolescents with Autism and ADHD: A Systematic Review and Meta-Analysis, PMC — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11049008/
• CDC, Symptoms of ADHD: https://www.cdc.gov/adhd/signs-symptoms/