Screening for autism in older and younger toddlers with the Modified Checklist for Autism in Toddlers

Autism. 2008 Sep;12(5):513-35. doi: 10.1177/1362361308094503.


The Modified Checklist for Autism in Toddlers (M-CHAT) was used to screen younger (16-23 months) versus older (24-30 months) high- and low-risk toddlers. Refusal rates for follow-up interview showed no group differences, but parents of younger/low-risk children were more likely to refuse evaluation than parents of high-risk children. PPP for an ASD diagnosis was: younger/high-risk 0.79, older/high-risk 0.74, younger/low-risk 0.28, and older/low-risk 0.61, with PPP differing by age within the low-risk group. Most of the children in all groups, however, were diagnosed with a developmental disorder. Symptom severity generally did not differ among groups. Cognitive and adaptive measures showed minimal group differences. Therefore, older and younger toddlers had similar symptomatology and developmental delays; PPP for ASD is better at 24 than 18 months for low-risk children; however, these children are still highly likely to show a developmental disorder. Clinical decision making should balance early identification against the lower specificity of M-CHAT screening for the younger/low-risk group.

Publication types

  • Validation Study

MeSH terms

  • Autistic Disorder / diagnosis*
  • Autistic Disorder / epidemiology*
  • Child, Preschool
  • Female
  • Humans
  • Male
  • Mass Screening / methods*
  • Observer Variation
  • Surveys and Questionnaires*