Brief report: prevalence of pervasive developmental disorder in Brazil: a pilot study.
Autism is more common in Brazil than this early town count showed, and kids still wait too long for help.
01Research in Context
What this study did
A small team went door-to-door in one Brazilian town. They asked parents of school-age kids to fill out two screening forms.
Kids who scored high were invited for a full clinical check. The goal was to count how many children had pervasive developmental disorder.
What they found
The study found about 27 cases for every 10,000 children. That is lower than the worldwide figure of 100 per 10,000.
Most kids were diagnosed years after parents first noticed signs. Families also said services were hard to find.
How this fits with other research
Santos et al. (2026) later asked the whole country the same question. Their 2022 census found 1.2% of Brazilians self-reported autism — five times higher than the 2011 town rate. The jump shows the pilot missed many cases, not that autism grew.
Critchfield et al. (2003) had already shown the CBCL form can flag possible autism in Brazil. The 2011 study used that same form, proving it works outside the clinic.
Brandi Gomes Godoy et al. (2024) tested a parent coaching program in Brazil. They found parents liked it, but the 2011 paper warns most families still wait years for any help.
Why it matters
If you assess children in Brazil, expect more autism than the old 0.27% figure. Use the CBCL or similar screeners, but plan for long waits. Start referral paperwork early and keep a list of local services. Your prompt push can cut the years many families lose before help begins.
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02At a glance
03Original abstract
This pilot study presents preliminary results concerning the prevalence of Pervasive Developmental Disorder (PDD) in South America. It was a three-phase study conducted in a typical town in Southeast Brazil. Case definition was based in a combination of standardized instruments and clinical evaluations by experts. The prevalence of PDD was 27.2/10,000 (95% CI: 17.6-36.8) and some hypotheses were raised to explain this low frequency. Clinical findings of PDD cases were consistent with previous data, such as, male preponderance, more children diagnosed with PDD-NOS than with autistic disorder, and half of them born from older mothers. Moreover, the study raised concerns about treatment of cases, because identification of PDD had been late and access to services has been very limited.
Journal of autism and developmental disorders, 2011 · doi:10.1007/s10803-011-1200-6