Developmental trajectories in children with and without autism spectrum disorders: the first 3 years

Child Dev. Mar-Apr 2013;84(2):429-42. doi: 10.1111/j.1467-8624.2012.01870.x. Epub 2012 Oct 30.


Retrospective studies indicate 2 major classes of autism spectrum disorder (ASD) onset: early and later, after a period of relatively healthy development. This prospective, longitudinal study examined social, language, and motor trajectories in 235 children with and without a sibling with autism, ages 6-36 months. Children were grouped as: ASD identified by 14 months, ASD identified after 14 months, and no ASD. Despite groups' initial similar developmental level at 6 months, ASD groups exhibited atypical trajectories thereafter. Impairment from 14 to 24 months was greater in the Early-ASD than the Later-ASD group, but comparable at 36 months. Developmental plateau and regression occurred in some children with ASD, regardless of timing of ASD diagnosis. Findings indicate a preclinical phase of varying duration for ASD.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Child Development / physiology*
  • Child Development Disorders, Pervasive / physiopathology*
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Language*
  • Male
  • Motor Skills / physiology*
  • Prospective Studies
  • Psychological Tests
  • Siblings
  • Social Behavior*
  • Time Factors