Prevalence of autism and attention-deficit-hyperactivity disorder in Down syndrome: a population-based study

Dev Med Child Neurol. 2017 Mar;59(3):276-283. doi: 10.1111/dmcn.13217. Epub 2016 Aug 9.


Aim: To investigate the prevalence of autism spectrum disorder (ASD) and attention-deficit-hyperactivity disorder (ADHD) in a population-based group of children and adolescents with Down syndrome, and to relate the findings to level of intellectual disability and to medical conditions.

Method: From a population-based cohort of 60 children and adolescents with Down syndrome, 41 individuals (29 males, 12 females; mean age 11y, age range 5-17y) for whom parents gave consent for participation were clinically assessed with regard to ASD and ADHD. The main instruments used were the Autism Diagnostic Interview-Revised, Autism Diagnostic Observation Schedule, Swanson, Nolan, and Pelham-IV Rating Scale, and the Adaptive Behavior Assessment System-II.

Results: High rates of ASD and ADHD were found: 17 (42%) and 14 (34%) of the 41 children met DSM criteria for ASD and ADHD respectively.

Interpretation: Children with Down syndrome and coexisting neurodevelopmental/neuropsychiatric disorders in addition to intellectual disability and medical disorders constitute a severely disabled group. Based on the results, we suggest that screening is implemented for both ASD and ADHD, at the age of 3 to 5 years and early school years respectively, to make adequate interventions possible.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Attention Deficit Disorder with Hyperactivity / epidemiology*
  • Attention Deficit Disorder with Hyperactivity / etiology*
  • Autistic Disorder / epidemiology*
  • Autistic Disorder / etiology*
  • Child
  • Child, Preschool
  • Cohort Studies
  • Community Health Planning
  • Down Syndrome / complications*
  • Down Syndrome / epidemiology
  • Female
  • Humans
  • Male
  • Neurologic Examination
  • Prevalence
  • Psychiatric Status Rating Scales