Danish study links surge in ADHD and autism diagnoses to shifting identification practices
A large Danish study of over 2.1 million children found that those diagnosed with ADHD or autism today are more similar to the general population than those diagnosed a decade ago. This suggests that rising diagnosis rates may partly stem from broader identification and changing diagnostic patterns, not solely an increase in underlying conditions. The research was published in JAMA Psychiatry.
The study analyzed over 2.1 million Danish children and adolescents, comparing more than 71,000 diagnosed individuals with over 713,000 undiagnosed peers between 2012 and 2022. Researchers tracked characteristics previously associated with ADHD and ASD, including premature birth, low birth weight, parental education and income levels, parental psychiatric history, and pre-diagnosis healthcare usage.
The narrowing gap was substantial. Low birth weight's association with later diagnosis fell from a 54% increased likelihood to just 17% over the decade. Similar declines appeared for premature birth and socioeconomic disadvantage measures. The researchers emphasize these risk factors remain relevant, but the diagnosed population now more closely mirrors the general population than before.
This research could reshape public understanding of rising neurodevelopmental diagnoses. If broader identification practices explain part of the increase, families may feel less alarm about an apparent epidemic, while clinicians might reconsider diagnostic thresholds. Education systems and healthcare providers could face growing demand for services as more children receive diagnoses, potentially straining resources. Policymakers may need to weigh whether expanded identification reflects genuine need or overdiagnosis, though the study does not resolve that question definitively.