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

Yes, a child can have both autism and ADHD. Clinicians call this comorbidity or co-occurrence, and since the DSM-5 in 2013 they can diagnose the two together. In U.S. parent-survey data, about 44% of children with autism also had ADHD, and about 14% of children with ADHD also had autism. Having both can slow down diagnosis and make it harder to tell which condition is driving which behavior, but there are research-backed ways to support a child who has both.

This guide covers how common the overlap is, how the two conditions differ, how a dual diagnosis works, what treatment research shows, and where ABA fits.

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.

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)

ADHD care typically includes behavioral parent training and classroom supports, medication, or a combination, directed by the child's physician or psychologist. ABA shares some of those behavioral principles, such as reinforcement and structured routines, but it is designed and studied mainly for autism, so we don't present it as a stand-alone ADHD treatment.

What a BCBA can do for an autistic child who also has ADHD: assess why behaviors happen, teach skills like waiting, transitioning and staying with a task, build routines that reduce overwhelm, and coordinate with the school and the clinicians managing ADHD. Our guide to parent coaching in ABA shows how those skills carry over at home.

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.

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.

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/