Behavior Genetics

, Volume 25, Issue 6, pp 537–544

Childhood hyperactivity scores are highly heritable and show sibling competition effects: Twin study evidence


  • Anita Thapar
    • Department of Psychological MedicineUniversity of Wales College of Medicine
  • Amaia Hervas
    • Department of Child and Adolescent PsychiatryInstitute of Psychiatry
  • Peter McGuffin
    • Department of Psychological MedicineUniversity of Wales College of Medicine

DOI: 10.1007/BF02327577

Cite this article as:
Thapar, A., Hervas, A. & McGuffin, P. Behav Genet (1995) 25: 537. doi:10.1007/BF02327577


Hyperactivity has consistently been shown to be familial. Until recently however, due to a lack of systematic twin evidence, it has remained uncertain to what extent familial transmission can be explained by genetic factors. We used a systematically ascertained population-based sample of twin pairs aged between 8 and 16 years old to explore the role of genetic influences on maternally rated hyperactivity scores. Hyperactivity scores were found to be substantially heritable. The data were best explained by a model which incorporated sibling competitive effects as well as additive genetic factors. These findings suggest not only that hyperactivity scores are influenced by genetic factors but that sibling interaction effects are also of importance.

Key Words

Twin studieshyperactivityattention deficit hyperactivity disordersibling interaction
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© Plenum Publishing Corporation 1995