Stability and change in autism spectrum disorder diagnosis from age 3 to middle childhood in a high-risk sibling cohort.
Age-3 autism diagnosis is 90 % stable, yet 1 in 8 high-risk siblings first missed later qualify—so keep monitoring.
01Research in Context
What this study did
Lovell et al. (2016) followed 192 high-risk siblings from age 3 to about age 9.5. All kids got a full clinical best-estimate autism diagnosis at age 3. The team repeated the same gold-standard tests six years later to see who still met criteria.
They counted how many early diagnoses stayed the same and how many new cases appeared.
What they found
Nine out of ten children kept the exact same diagnosis. Ninety-four percent of kids called ASD at age 3 still qualified six years later. Another 12 percent who were first labeled non-ASD later met full criteria.
In plain numbers: the label you give at age 3 is usually the label that sticks, but one in eight initially missed will need services later.
How this fits with other research
Sasson et al. (2018) looked at German insurance codes and saw only one-third of early ASD labels survived five years. The huge gap—90 % versus 33 %—looks like a contradiction, but it isn’t. Jessica’s team used long, in-person evaluations; J et al. counted quick billing codes. Clinic-level care gives sharper, more stable calls.
Burack et al. (2004) tracked self-regulation for two years and also found steady traits, backing the idea that core autism features don’t swing wildly over time.
Leng et al. (2024) show migrant kids often get diagnosed late. Pair that with Jessica’s 12 % late-identified group and you see why watching high-risk toddlers past age 3 matters.
Why it matters
You can trust a thorough age-3 diagnosis for long-range planning, but don’t close the file. Keep yearly screens for any high-risk sibling who missed the cutoff—12 % will bloom into clear ASD by middle childhood. Use the same gold-standard tools (ADOS, ADI-R) at each visit so your data match the 90 % stability benchmark.
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02At a glance
03Original abstract
Considerable evidence on autism spectrum disorder emergence comes from longitudinal high-risk samples (i.e. younger siblings of children with autism spectrum disorder). Diagnostic stability to age 3 is very good when diagnosed as early as 18-24 months, but sensitivity is weaker, and relatively little is known beyond toddlerhood. We examined stability and change in blinded, clinical best-estimate diagnosis from age 3 to middle childhood (mean age = 9.5 years) in 67 high-risk siblings enrolled in infancy. Good agreement emerged for clinical best-estimate diagnoses (89.6% overall; kappa = 0.76, p < 0.001, 95% confidence interval = 0.59-0.93). At age 3, 18 cases (26.9%) were classified with "autism spectrum disorder": 17 retained their autism spectrum disorder diagnosis (94.4%; 13 boys, 4 girls) and 1 no longer met autism spectrum disorder criteria at follow-up. Among "non-autism spectrum disorder" cases at age 3, 43/49 remained non-autism spectrum disorder at follow-up (87.8%; 22 boys, 21 girls) and 6/49 met lower autism symptomatology criteria ("Later-Diagnosed"; 3 boys, 3 girls). Later-diagnosed cases had significantly lower autism spectrum disorder symptomatology and higher receptive language at age 3 and trends toward lower autism symptoms and higher cognitive abilities at follow-up. Emerging developmental concerns were noted in all later-diagnosed cases, by age 3 or 5. High-risk children need to be followed up into middle childhood, particularly when showing differences in autism-related domains.
Autism : the international journal of research and practice, 2016 · doi:10.1177/1362361315614979