Rising autism diagnoses reflect broader criteria, not a true surge

Autism diagnoses have risen sharply. A U.S. survey found that nearly four percent of children were labeled with autism between 2013 and 2022, while a global review gave a median of about one percent. The wide spread—from 1.09 to 436 per ten thousand—reflects differences in study design, not a biological surge. England and Northern Ireland recorded a 787 percent rise in primary‑care diagnoses, yet the average age at diagnosis climbed from 9.6 to 14.5 years.

Drivers of the increase

The rise is driven by changes in who is diagnosed. Swedish registry data show more adults and females are being labeled, with females outnumbering males between ages 15 and 24 by 2022. Australia’s staggered rollout of a disability‑funding scheme produced a 32 percent increase in reported prevalence, especially in metropolitan areas, and the effect was stronger for males—evidence that a lowered recognition threshold, not a catch‑up of under‑diagnosed girls, is at work.

Screening studies that keep measurement constant give a clearer view of underlying prevalence. In a South Korean city, researchers screened every seven‑year‑old entering elementary school over 12 years and found a stable 2–3 percent prevalence. The proportion of children meeting diagnostic criteria did not rise, showing that administrative counts rise mainly due to detection. Meanwhile, the share of diagnosed cases with intellectual disability fell from over 55 percent in 2001 to under seven percent in 2020, indicating that milder cases now drive most of the increase.