Autism Symptoms and Behavioural Disturbances in ~500 Children with Down Syndrome in England and Wales

Background: Recent research (DiGuiseppi et al., 2010; Moss et al., 2012) shows that a significant minority of children with Down syndrome (DS) also meet diagnostic criteria for an autism spectrum disorder (ASD). These children demonstrate a distinct behavioural profile and have been reported to show higher levels of stereotyped behaviour, repetitive language, overactivity and self-injury than children with typical DS (Moss et al., 2012).

Objectives: The present study explored rates of autism symptoms and associated behaviour problems in children aged 6-15 years with DS in England and Wales.

Methods:  Potential participants (N=1382) were recruited via the UK Down’s Syndrome Association. The Social Communication Questionnaire (SCQ; Rutter et al., 2003) was used to screen for autistic symptoms and the Strengths and Difficulties Questionnaire (SDQ; Goodman, 1997) to explore behavioural difficulties. The survey also investigated developmental regression.

Results:  Questionnaires were completed by 507 families (37% of the cohort; however 8 responses were excluded because age was not indicated or fell outside the inclusion boundaries). The proportion of children who met the cut-off score on the SCQ for ASD (total score ≥15) was 37.7% (95% confidence interval [CI]: 33.4% - 42.0%) and for autism (total score ≥22) 16.5% (95% CI: 13.2% - 19.8%). Children who met the cut-off for ASD were significantly more likely to be reported as having emotional symptoms (Z=5.48, p<.001, r=0.29), conduct problems (Z=5.96, p<.001, r=0.31) and hyperactivity (Z=8.15, p<.001, r=0.42) on the SDQ than children who scored well below cut-off (total score <10). Developmental regression, in both language and general skills, was also higher in the ASD group. However, odds ratio analysis of item specific responses using an autism reference group (Moss et al., In press) indicated that the profile of their autism symptoms on the SCQ was atypical compared to children with idiopathic ASD. 

Conclusions: The pervasiveness of ASD in children with DS in England and Wales is substantially higher than in the general population. These children experience significantly greater behavioural problems than children with DS only. Early detection of autistic symptoms is essential for the provision of appropriate intervention. However, the atypical ASD profile may affect the recognition of the disorder and inhibit the implementation of autism specific interventions.

References:

DiGuiseppi, C., Hepburn, S., Davis, J., Fidler, D., Hartway, S., et al. (2010) Screening for autism spectrum disorders in children with Down syndrome, Journal of Developmental & Behavioural Pediatrics, 31, 181-191.

Goodman, R. (1997). The strengths and difficulties questionnaire: A research note. Journal of Child Psychology and Psychiatry and Allied Disciplines, 38(5), 581-586.

Moss, J., Richards, C., Nelson, L. & Oliver, C. (2012) Prevalence of autism spectrum disorder symptomology and related behavioural characteristics in individuals with Down syndrome. Autism, 0(0) 1-15.

Moss, J., Oliver, C., Nelson, L., Richards, C., & Hall, S. (In press). Delineating the profile of Autism Spectrum Disorder characteristics in Cornelia de Lange and Fragile X Syndromes. American Journal of Intellectual and Developmental Disabilities.

Rutter, M., Bailey, A., Lord, C. & Berument, S. (2003) The Social Communication Questionnaire. Los Angeles, CA: Western Psychological Services.