When Maria Jensen’s son was diagnosed with autism in 2018 at age seven, his teachers praised her for catching it early—yet his challenges were subtle: difficulty with transitions, a preference for routine, and a quiet intensity during play. Just two decades earlier, children like him might never have been identified. Now, a landmark study of over 37,000 Danes reveals a quiet genetic shift: people diagnosed today with autism or ADHD carry a lower genetic risk burden than those diagnosed in the 1990s. This isn’t because the conditions are disappearing—it’s because we’re seeing them more clearly, in more people, and across a broader spectrum.
For years, rising diagnosis rates of autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) have sparked alarm, with speculation pointing to environmental toxins, screen time, or modern lifestyles. But the real story may lie not in what’s changing biologically, but in how we define and detect these conditions. Published in JAMA Psychiatry, the study analyzed genetic data from Danes diagnosed between 1994 and 2016, calculating polygenic risk scores (PRS)—a measure of inherited genetic predisposition. The results were striking: for every 10 years, the average genetic risk score dropped significantly among newly diagnosed individuals. Those diagnosed in 2016 had notably lower genetic loading for both ASD and ADHD than those diagnosed in 1996.
Even more telling, the decline wasn’t limited to the diagnosed condition. People newly diagnosed with ADHD or ASD also showed lower genetic risk for schizophrenia, bipolar disorder, and other psychiatric conditions—suggesting today’s diagnoses are not misdirected cases of other illnesses, but rather milder, previously overlooked presentations. This supports the theory that broader diagnostic criteria and greater awareness—especially of subtle or atypical symptoms—are expanding the pool of who gets diagnosed. In the past, only those with more pronounced traits were identified; now, clinicians are recognizing the full spectrum.
The implications are profound. A fourfold to tenfold increase in diagnoses across some populations isn’t necessarily a crisis—it may be a sign of progress. It means children like Maria’s son are getting support earlier, in school and at home, without having to meet a narrow, outdated threshold. It also means research and services must adapt to serve a more diverse group of individuals, not all of whom face the same challenges.
As diagnostic boundaries continue to evolve, so too must our understanding of what it means to live with ADHD or autism. The genetic signal is fading not because the conditions are less real, but because our lens is widening—finally capturing the full diversity of human neurology.