Variation in early developmental course in autism and its relation with behavioral outcome at 3-4 years of age.
How autism starts does not predict later IQ or severity—base treatment on today’s assessment, not parent-reported onset story.
01Research in Context
What this study did
Warnes et al. (2005) asked 100 parents to recall when their child first showed autism signs. They split kids into early-onset, late-onset, and regression groups. All children took IQ and autism tests at 3-4 years old.
The team wanted to know if the age or way autism appeared predicted later ability or symptom severity.
What they found
Early signs showed up as early as 3-6 months, but the timing did not matter. Kids who lost skills did not score worse than kids who had slow, steady delays.
IQ and autism severity at were the same across all onset groups.
How this fits with other research
Mount et al. (2011) later counted regression in a large share of the kids with ASD and also found it did not run in families. This larger set backs up Emily’s null result.
Van Hanegem et al. (2014) tracked kids longer and saw four steady severity paths from 2½-5½ years. The paths did not link to how autism started, echoing the 2005 finding.
Kuang et al. (2025) seems to clash. Their model used 6-24 month BSID scores to spot later ASD in preterm babies. But they looked at current skills, not parent stories. Both papers agree: use today’s data, not old tales, to plan help.
Why it matters
Stop asking parents exactly when regression happened. It won’t tell you how hard to program. Instead, run current VB-MAPP or AFLS, pick targets from today’s scores, and move on. Early onset story is trivia; present skills drive intervention.
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02At a glance
03Original abstract
The aims of the present study were to describe variations in the early course of development in autism by utilizing an in-depth parent interview that incorporated techniques to improve accuracy of parent recall, and to examine the relation between variations in early developmental course in autism and behavioral outcome at 3-4 years of age. The Early Development Interview, which consisted of questions about child's behavior in several domains from birth through 2 years of age, was created and administered to parents of 72 3-4-year-old children with autism spectrum disorder and 34 3-4-year-old children with developmental delay, who were matched on mental and chronological age, and 39 1-4-year-old typically developing children, who were matched to the clinical groups on mental age. At 3-4 years of age, children were administered standardized measures (some clinician administered and some parent report); these included verbal and nonverbal IQ, autism symptom severity, and adaptive and aberrant behavior. Based on the Early Development Interview, children with autism spectrum disorder (ASD) were reported to have elevated symptoms in the social and regulatory domains by 3-6 months. By 12-15 months, parents of children with ASD reported significantly higher levels of social symptoms than parents of children with developmental delay. At 3-4 years of age, children with autism with early vs. late onset of symptoms, and with vs. without a history of loss of skills (regression) were not found to differ on standardized tests of verbal and nonverbal IQ and observational measures of autism symptom severity.
Journal of autism and developmental disorders, 2005 · doi:10.1007/s10803-005-3301-6