Autism under age 3 years: a clinical study of 28 cases referred for autistic symptoms in infancy

J Child Psychol Psychiatry. 1990 Sep;31(6):921-34. doi: 10.1111/j.1469-7610.1990.tb00834.x.


Twenty-eight children referred with a preliminary diagnosis of autistic disorder under age 3 yrs were extensively examined from the neuropsychiatric point of view and followed up for several months to several years. A diagnosis of autistic disorder was confirmed in 75% of the cases. A variety of associated medical conditions was identified. It was concluded that autism can be diagnosed in a substantial proportion of cases before age 3 yrs and that the neurobiological background is similar to that seen in older autistic children.

MeSH terms

  • Autistic Disorder / diagnosis*
  • Autistic Disorder / psychology
  • Child Development
  • Child Development Disorders, Pervasive / diagnosis
  • Child, Preschool
  • Diagnosis, Differential
  • Female
  • Follow-Up Studies
  • Humans
  • Infant
  • Intellectual Disability / diagnosis
  • Language Development Disorders / diagnosis
  • Male
  • Neuropsychological Tests
  • Prospective Studies
  • Referral and Consultation*
  • Retrospective Studies
  • Rett Syndrome / diagnosis
  • Risk Factors
  • Social Environment