Autism rates hold steady, challenging ‘epidemic’ claims

Clinical takeaway: Rising autism diagnoses may reflect improved detection rather than a true increase in autism occurrence, according to a large population-based study. Clinicians should remain alert for autism in children who may be overlooked by traditional referral pathways, particularly girls and children without intellectual disability.

Reported autism prevalence has increased dramatically over recent decades, fueling concerns about an “autism epidemic.” However, many estimates are based on administrative or service-based data that can be influenced by changing diagnostic practices, awareness, and access to services.

In this South Korean cohort study, investigators prospectively screened more than 62,000 children from 12 consecutive birth cohorts born between 1998 and 2010 and assessed autism spectrum disorder (ASD) at age 7 using standardized diagnostic evaluations. Across cohorts, neither 7-year cumulative incidence nor prevalence increased over time. ASD incidence ranged from 1.9% to 3.2%, while prevalence ranged from 2.0% to 3.4%, with no significant upward trend.

Boys consistently had higher rates of ASD than girls, but researchers found that girls were disproportionately represented among previously unidentified cases discovered through population screening rather than through clinical or educational services. Overall, nearly one-quarter of children diagnosed with ASD during detailed assessments had never previously received an autism diagnosis or intervention.

Children with previously undiagnosed ASD generally had stronger cognitive and adaptive functioning and were less likely to have intellectual disability than children already connected to services. However, they still frequently had coexisting psychiatric conditions, suggesting that autism may be missed when symptoms overlap with anxiety, mood, or behavioral disorders.

The authors observed a modest shift over time from previously undiagnosed to service-identified cases, consistent with improving recognition rather than increasing disease occurrence. “This pattern suggests improved detection rather than increased ASD occurrence and does not support an ASD epidemic in this population,” the authors concluded.

Source: Kim YS, et al. (2026 Sep 14) JAMA Pediatr. Cumulative Incidence and Prevalence of Autism Spectrum Disorder