A twin study of autism in Denmark, Finland, Iceland, Norway and Sweden

J Child Psychol Psychiatry. 1989 May;30(3):405-16. doi: 10.1111/j.1469-7610.1989.tb00254.x.


The Nordic countries were screened for the occurrence of cases of autism with a same-sexed twin under age 25 years. Twenty-one pairs (11 monozygotic and 10 dizygotic) of twins and one set of identical triplets were found and extensively examined. The concordance for autism by pair was 91% in the monoygotic and 0% in the dizygotic pairs. The corresponding concordances for cognitive disorder were 91% and 30%, respectively. In most of the pairs discordant for autism, the autistic twin had more perinatal stress. The results lend support for the notion that autism sometimes has a hereditary component and that perinatal stress is involved in some cases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Autistic Disorder / genetics*
  • Autistic Disorder / psychology
  • Brain Damage, Chronic / genetics
  • Child
  • Child Behavior Disorders / genetics
  • Child, Preschool
  • Diseases in Twins*
  • Female
  • Fragile X Syndrome / genetics
  • Humans
  • Iceland
  • Learning Disabilities / genetics
  • Male
  • Risk Factors
  • Scandinavian and Nordic Countries
  • Social Environment
  • Twins, Dizygotic
  • Twins, Monozygotic