Prevalence and onset of regression within autism spectrum disorders: a meta-analytic review.
Roughly one in three children with autism lose early skills around 18 months, so watch closely and act quickly.
01Research in Context
What this study did
The team pooled 85 studies that together tracked 29,035 people with autism.
They asked: how many lose skills they once had, and when does that loss start?
Every study used parent report, medical charts, or direct exams to spot regression.
What they found
About one in three children with autism experience regression.
The average age of loss is roughly 18 months.
Rates look higher when parents are the ones answering questions.
How this fits with other research
Tan et al. (2021) updated these numbers with 75 newer studies and 33,014 kids. Their figure is 30%, almost the same, so the old estimate still holds.
Casey et al. (2009) saw 17-26% in one state’s records. The meta-analysis averaged many such reports, giving a more stable number than any single count.
Hu et al. (2024) took the 30% figure as fact and showed ABA helps regressive kids under four. The meta-analysis gives their treatment study a clear base rate to work from.
Why it matters
You can tell families that skill loss is common and usually shows up near the second birthday.
Because regressive autism is linked to later epilepsy and lower IQ (D et al. 2017), flag these kids early for full medical work-ups.
Start intervention fast—Hu et al. found the best ABA gains occur before age four.
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02At a glance
03Original abstract
Rates and onset of regression were meta-analyzed from 85 articles representing 29,035 participants with autism spectrum disorders (ASD). Overall prevalence rate for regression was 32.1, 95 % CI [29.5, 34.8] occurring at mean of 1.78 years, 95 % CI [1.67, 1.89]. Regression prevalence rates differed according to four types of regression: language regression, 24.9 %; language/social regression, 38.1 %; mixed regression, 32.5 %; and unspecified regression, 39.1 %. Regression prevalence also differed according to sampling method: population-based prevalence was 21.8 %, clinic-based prevalence was 33.6 %, and parent survey-based prevalence was 40.8 %. Risk of regression was equal for males and females, but higher for individuals diagnosed with autism versus another ASD. Later age of regression onset was predicted by older age of child.
Journal of autism and developmental disorders, 2013 · doi:10.1007/s10803-012-1621-x