Prevalence of comorbidity of autism and ADHD and associated characteristics in school population: EPINED study.
In real-world schools, autism plus ADHD is rare but almost always missed—so always screen for both.
01Research in Context
What this study did
Josefa and her team checked every child in 3-11 grade across one Spanish region.
They used DSM-5 rules to spot autism, ADHD, or both.
Parents, teachers, and doctors all gave reports.
The final count came from the kids.
What they found
Only 0.51 percent of the kids had both autism and ADHD.
That is about one child in every 200.
Boys outnumbered girls four to one.
Most striking: 84 percent of these kids had never been told they had both conditions.
How this fits with other research
Reus et al. (2013) showed that when ADHD is present, parent and interview autism scores go up.
This helps explain why Canals et al. (2024) found so many missed cases—clinicians may have trusted high scores and stopped looking.
Green et al. (2015) already saw more autism traits in elementary kids with ADHD, but they did not count full diagnoses.
Josefa’s work turns those earlier hints into a hard number for schools.
Ingadottir et al. (2025) will next compare thinking skills in Iceland after Josefa’s team mapped how common the overlap is.
Why it matters
If you screen for only one label, you will miss the other four times out of five.
Add a quick ADHD checklist every time you assess for autism, and vice versa.
Early dual diagnosis means you can write plans that tackle both social and attention needs from day one.
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02At a glance
03Original abstract
Autism and attention deficit hyperactivity disorder (ADHD) comorbidity in the school population have been understudied. This study estimates its prevalence considering both parents' and teachers' reports and clinical diagnosis. Sociodemographic, clinical, and cognitive data were compared by diagnostic groups: autism, ADHD, autism and ADHD, subthreshold autism spectrum disorder (ASD), subthreshold ADHD, and children without neurodevelopmental conditions. Following a two-phase design, 3727 parents and teachers (1802 preschoolers, 1925 school-age children) participated in the first phase. Subsequently, 781 participants underwent individual assessment for DSM-5 diagnoses. The estimated prevalence of the comorbid diagnosis was 0.51% (0.28%-0.74%), with significant sex differences (0.16% girls, 0.89% boys). The cooccurrence of symptoms of autism and ADHD reported by parents or teachers was 3.2% and 2.6%, respectively. ADHD comorbidity was observed in 32.8% of autistic children and 31.4% of those with subthreshold ASD. ASD comorbidity was observed in 9.8% of children with ADHD and 5.7% of those with subthreshold ADHD. Comorbidity was reported by at least one informant in 95% of children. Only 15.8% of children with autism and ADHD had been previously diagnosed with both conditions. Early detection and accurate comorbidity diagnosis are crucial to address the clinical and socio-educational needs of these children.
Autism research : official journal of the International Society for Autism Research, 2024 · doi:10.1002/aur.3146