A major JAMA Psychiatry study of over 2.1 million Danish children finds the rise in ADHD and autism diagnoses is driven mainly by better detection and access, not a sudden increase in underlying risk. Researchers tracked more than 71,000 diagnosed youth from 2012–2022 and observed that traditional risk gaps (for example, low birth weight) narrowed markedly. The study credits greater awareness, improved screening, expanded access, and shifting diagnostic practices, and calls for similar research outside Denmark.
Why ADHD and Autism Diagnoses Have Risen — New Danish Study Shows It's Largely Better Detection
Analyzing 71,000 cases from 2012 to 2022, researchers at ISGlobal find the statistical gap between newly diagnosed neurodivergent youth and the general population is rapidly closing. ©Image Credit: Unsplash / Peter Burdon
Recent increases in ADHD and autism diagnoses largely reflect improved detection and broader access to evaluation, not necessarily a sudden rise in underlying risk, according to a large study published in JAMA Psychiatry.
Study Design and Scope
A research team from the Barcelona Institute for Global Health (ISGlobal) and Aarhus University analyzed health records for more than 2.1 million children and adolescents in Denmark. They followed over 71,000 individuals diagnosed with attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder (ASD) between 2012 and 2022, comparing them with more than 713,000 peers who had not received those diagnoses.
Key Findings
Historically, diagnoses were concentrated among children with clear risk markers: premature birth or low birth weight, lower parental income or education, a family history of psychiatric disorders, and heavy use of medical services prior to diagnosis. The study found that over the decade these differences narrowed — diagnosed children today more closely resemble the general population than those diagnosed a decade ago.
"The key message is not that these risk factors are no longer important. What we found is that people diagnosed in recent years resemble the general population more closely than those who received the same diagnoses a decade ago," said co-author Magnus Elias Tarp.
For example, children born with low birth weight were 54% more likely to receive an ADHD or ASD diagnosis in 2012 compared with normal-weight peers; by 2022 that gap had fallen to 17%. Similar declines were seen for preterm birth and socioeconomic indicators.
Why Diagnoses Are Increasing
The authors point to several overlapping explanations for the rise in diagnosed cases:
- Greater public awareness: Families, teachers, and clinicians now recognize neurodevelopmental signs more readily.
- Improved screening: Schools and healthcare settings use better screening tools and referral pathways.
- Expanded access: Broader access to health services makes formal evaluations more attainable.
- Evolving clinical thresholds: Diagnostic practices and thresholds for identifying impairment have changed, bringing more people into care.
Interpretation and Next Steps
Senior author Oleguer Plana-Ripoll emphasized that these results do not show that conditions are less severe or that diagnoses are simply being handed out indiscriminately. Instead, the pattern indicates broader identification of people who previously lacked access to assessment and support. The researchers recommend repeating similar studies in other countries to see whether the same trends appear elsewhere.
Sources: JAMA Psychiatry; ScienceDaily. The study is based on Danish registry data and reflects the healthcare and diagnostic context there.
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