Determinants of an autism spectrum disorder diagnosis in childhood and adolescence: Evidence from the UK Millennium Cohort Study.
Mariko Hosozawa, Amanda Sacker, William Mandy and 3 others
PMID 32367727WHAT IT FOUND
Only 21.4% of children with parent-reported autism in this UK cohort were diagnosed before school, and 27.9% after secondary school entry.
Typical cognitive scores and absent early parental concern were linked to later diagnosis.
Key findings
01Of 581 children with parent-reported ASD by age 14, 126 (21.4%) were diagnosed before school, 300 (50.7%) during primary school and 155 (27.9%) during secondary school.
02Low household income was associated with later diagnosis, while having parental concerns at age 5 was associated with diagnosis before school.
03Children in the typical cognitive range were twice as likely as children with cognitive delay to be diagnosed during secondary school.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The diagnosis was parent-reported and not externally validated, so some reported diagnoses may be wrong or some diagnoses may have been missed. The study did not directly assess autism symptom severity, so later diagnosis could reflect milder symptoms, camouflaging or other factors not measured. All predictors were measured at age 5, so it cannot describe the full referral or assessment pathway before and after that point. Missing data were imputed, with missingness up to 25.9% for teacher-rated social development. The analysis shows associations, not causes; low income, absent parental concern and typical cognitive scores may be markers of a more complex diagnostic pathway. The study lacked detailed information on healthcare use and other psychiatric diagnoses, so it cannot say which part of the diagnostic process to target.
Declared interests
The authors declared no potential conflicts of interest. Funding was from the Medical Research Council, UK Economic and Social Research Council, National Institutes of Health Research, Autistica and the Japan Foundation for Paediatric Research.
The easy way to misread this
Do not read typical cognitive scores as evidence against autism. In this cohort, children with typical cognitive scores were more likely to be diagnosed during secondary school, but the study did not measure symptom severity and cannot show that later diagnosis was caused by milder autism.