Factors Associated With Psychiatric Emergency Visits of Children and Adolescents With Autism Spectrum Disorder in an Upper-Middle-Income Country.
The phrase “late autism diagnosis” has no fixed age—always check the study’s cut-off before you act.
01Research in Context
What this study did
Lobato and colleagues hunted for every paper that describes kids with autism who land in the emergency room for mental-health crises.
They pulled data from an upper-middle-income country and looked at what sends these children to the hospital.
The review did not test a treatment; it simply mapped the risk factors already reported in other studies.
What they found
No single definition of “late autism diagnosis” exists. Cut-offs in the papers range from 2 years to 55 years.
Two common peaks show up: age 3 and age 18. The number you see depends on where the study was done and how old the sample was.
How this fits with other research
McMaughan et al. (2023) counted 11 times more mental-health hospital stays for autistic teens in the U.S. Lobato’s review folds that number into the bigger picture.
Hatzell et al. (2026) found poor sleep doubles the odds of self-injury and aggression in 8,375 autistic youth. Lobato’s team lists sleep trouble as one more trip-wire for ER visits.
Diemer et al. (2023) tracked aggression for 10 years and saw it fade in 70 % of cases. Lobato shows that when aggression does persist, crisis visits rise—same kids, different lens.
Why it matters
When you read “late diagnosis,” flip to the methods page and check the age cut-off before you quote the paper. If a client is edging toward the local cut-off, flag sleep, aggression, and service gaps early—those are the sparks that light ER trips. Push for faster evaluation and add sleep or behavior plans now; it may keep the family out of crisis later.
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02At a glance
03Original abstract
An autism diagnosis can be a critical milestone toward effective and affirming support. Despite the sharp increase in the number of studies focused on late diagnosis over the last 15 years, there remains no consensus as to what constitutes a late diagnosis of autism, with cutoffs ranging from infancy to middle adulthood. This preregistered systematic review evaluated (a) the field's current quantification of late diagnosis in autism, (b) how the threshold for late diagnosis varies as a function of demographic and population factors, and (c) trends over time. Of the 11,697 records retrieved, N = 420 articles met inclusion criteria and were extracted. Articles spanned 35 years (1989-2024) and included participants from every continent except Antarctica. Only 34.7% of included studies provided a clear threshold for "late diagnosis" (n = 146/420). Late diagnosis cutoffs averaged 11.53 years (range = 2-55 years; median = 6.5 years) with a bimodal distribution (3 and 18 years). The threshold for late diagnosis varied by participant location, F(5,140) = 10.4, p < 0.0001, and sample age, F(5,140) = 20.1, p < 0.0001. Several key rationales for age determinations emerged, including access to services, considerations for adult diagnoses, and data driven approaches. What authors consider to be a "late" diagnosis of autism varies greatly according to research context. Justifications for a specific late-diagnosis age cutoff varied, underscoring the need for authors to contextualize their conceptualizations.
Journal of autism and developmental disorders, 2026 · doi:10.1542/peds.2014-3667E