The prevalence of autism spectrum disorders in toddlers: a population study of 2-year-old Swedish children.
Systematic screening at age two quadruples autism prevalence by finding mild cases early.
01Research in Context
What this study did
Doctors in Gothenburg, Sweden checked every young learners for autism. They used a short toddler screen plus a full follow-up exam.
Before the project, only kids with clear delays got tested. The new plan caught kids who had been missed.
What they found
Diagnosed autism jumped from 4–the kids per 10 000 to 80 per 10 000. One simple screening round quadrupled the count.
Most new cases were mild or average IQ. Without the screen, these toddlers would have slipped through until school age.
How this fits with other research
Goodwin et al. (2012) wrote a guide that tells pediatric offices to screen at 18 and 24 months. Gudrun’s numbers prove that advice works in real life.
Cao et al. (2023) did the same toddler check across China and found even more autism (1.17 %). The two studies together show early screening lifts counts in very different countries.
García-Zambrano et al. (2026) counted older Colombian kids with health records and got only 0.14 %. That lower rate looks like a clash, but it isn’t: registry data miss mild toddlers who show up only when you screen early.
Why it matters
If you assess toddlers, you will find more clients who need ABA. Push your local clinics to add the 24-month screen. Early cases mean earlier therapy, smaller skill gaps, and better long-term outcomes.
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02At a glance
03Original abstract
Autism Spectrum Disorder (ASD) is more common than previously believed. ASD is increasingly diagnosed at very young ages. We report estimated ASD prevalence rates from a population study of 2-year-old children conducted in 2010 in Gothenburg, Sweden. Screening for ASD had been introduced at all child health centers at child age 21/2 years. All children with suspected ASD were referred for evaluation to one center, serving the whole city of Gothenburg. The prevalence for all 2-year-olds referred in 2010 and diagnosed with ASD was 0.80%. Corresponding rates for 2-year-olds referred to the center in 2000 and 2005 (when no population screening occurred) were 0.18 and 0.04%. Results suggest that early screening contributes to a large increase in diagnosed ASD cases.
Journal of autism and developmental disorders, 2012 · doi:10.1007/s10803-011-1391-x