Prevalence of autism spectrum disorder symptomatology and related behavioural characteristics in individuals with Down syndrome.
One in five people with Down syndrome meet ASD cut-off and show more stereotypy, hyperactivity and self-injury, so universal screening is essential.
01Research in Context
What this study did
Schwichtenberg et al. (2013) screened people with Down syndrome for autism traits.
They used the Social Communication Questionnaire, a quick parent checklist.
The team then compared behaviour reports for DS-only and DS-plus-ASD groups.
What they found
One in five people with Down syndrome met the ASD cut-off.
The DS-plus-ASD group showed more hand flapping, repeated words, hyperactivity and self-hitting.
Some, but not all, of these behaviours looked like idiopathic autism.
How this fits with other research
Ding et al. (2017) later surveyed 674 youths and saw a higher rate: about one in three screened positive.
The bigger sample included wider age ranges, which may explain the jump.
Godfrey et al. (2019) added an ASD-only group and found kids with DS-plus-ASD show equal social and repetitive scores, unlike typical ASD where social scores are usually worse.
Together the papers say: expect lots of ASD flags in Down syndrome, but the mix of symptoms is its own pattern.
Why it matters
Screen every child with Down syndrome for autism, even if language is limited.
High rates of hyperactivity and self-injury in the ASD-positive subgroup mean you should add behaviour-reduction plans early.
Use the SCQ first, then follow with an autism-specific tool that accounts for cognitive delay.
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02At a glance
03Original abstract
We evaluated the proportion of individuals with Down syndrome (DS: N = 108) who met criteria for autism spectrum disorder (ASD) on the Social Communication Questionnaire and the severity of ASD-related symptomatology in this group. The proportions of individuals with DS meeting the cut-off for ASD and autism in this sample were 19% and 8%, respectively. We then evaluated the behavioural profile of individuals with DS who scored above cut-off for ASD (DS+ASD; N = 17) compared with those with DS-only (N = 17) and individuals with idiopathic ASD (N = 17), matched for adaptive behaviour skills and ASD symptom severity (ASD group only). Individuals in the DS+ASD and ASD-only groups showed more stereotyped behaviour, repetitive language, overactivity and self-injury than the DS-only group (p < .001). Individuals in the DS+ASD and DS-only groups appeared less withdrawn from their surroundings than those with ASD (p < .004). These findings indicate differences in the behavioural and cognitive profile of individuals with DS+ASD compared with those with DS-only, when controlling for adaptive behaviour skills. Individuals with DS+ASD show broad similarities with individuals with idiopathic ASD with regard to ASD and behavioural characteristics but may also show some areas of subtle difference from this group.
Autism : the international journal of research and practice, 2013 · doi:10.1177/1362361312442790