Implementation of the International Classification of Diseases 11th revision behavioural indicators for disorders of intellectual development with co-occurring autism spectrum disorder.
ICD-11 behavioural indicators give valid severity ratings for ID—especially useful when standard IQ/adaptive tests aren’t feasible—but take extra time when ASD is also present.
01Research in Context
What this study did
van der Miesen et al. (2024) tested the new ICD-11 behavioural indicators in kids and teens who have both intellectual disability and autism. Teams in four countries watched each child, talked to caregivers, and gave the usual IQ and daily-living tests. They compared the new checklist ratings to the old test scores to see if the labels matched.
What they found
The behavioural indicators put most children in the same severity group as the standard tests. Mild ID was flagged more often by the new checklist. Severe ID was picked up more by the old tests. Overall, the match was strong enough for clinic use.
How this fits with other research
de Bildt et al. (2011) did the same kind of cross-country check with the ADOS autism scale and also found good fit, showing these calibrations travel well. Maljaars et al. (2012) warned that DISCO-11 over-calls autism in kids with moderate or severe ID; the new ICD-11 tool seems to avoid that trap by leaning on behaviour instead of caregiver history. Nevin et al. (2005) showed the Children’s Social Behaviour Questionnaire adds value when Vineland scores blur autism and ID; the ICD-11 indicators now give a free, standard way to do the same split.
Why it matters
You can now rate ID severity without long IQ tests when a child can’t sit for them. Add the 20-minute ICD-11 behavioural indicators to your intake packet. If ASD is also suspected, bank extra time—caregiver questions take longer—but you’ll leave with a severity label insurers accept.
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02At a glance
03Original abstract
BACKGROUND: The classification of mental, behavioural and neurodevelopmental disorders in the World Health Organization's International Classification of Diseases 11th revision (ICD-11) includes a comprehensive set of behavioural indicators (BIs) within the neurodevelopmental disorders grouping. BIs can be used to assess the severity of disorders of intellectual development in situations in which standardised measures of intellectual functioning and adaptive behaviours are not available or feasible. This international study examines the implementation characteristics of the BIs and compares them to standardised measures for assessing the severity of intellectual impairment and adaptive behaviours in disorders of intellectual development and autism spectrum disorder (ASD). The clinical utility of the ICD-11 and the fidelity of its application in international clinical settings were also assessed. METHODS: A total of 116 children and adolescents (5-18 years old) with a suspected or established diagnosis of disorders of intellectual development were included across four sites [Italy (n = 18), Sri Lanka (n = 19) and two sites in India (n = 79)]. A principal component analysis was conducted to evaluate the application of the ICD-11 guidance for combining severity levels. RESULTS: Assessment using the BIs showed a higher proportion of individuals classified with mild severity, whereas the standardised measures indicated a higher proportion of severe ratings. Additionally, individuals with co-occurring ASD tended to have more severe impairments compared with those without ASD, as indicated by both BIs and standardised measures. Overall, the BIs were considered clinically useful, although more time and consideration were required when applying the guidelines for individuals with a co-occurring disorder of intellectual development and ASD. The principal component analysis revealed one principal component representing overall disorders of intellectual development severity levels. CONCLUSIONS: The ICD-11 BIs can be implemented as intended in international clinical settings for a broad range of presentations of individuals with neurodevelopmental disorders. Use of the BIs results in similar severity diagnoses to those made using standardised measures. The BIs are expected to improve the reliability of severity assessments in settings where appropriate standardised measures for intellectual and adaptive behaviours are not available or feasible.
Journal of intellectual disability research : JIDR, 2024 · doi:10.1111/jir.13146