Family, twin, and adoption studies of bipolar disorder

Am J Med Genet C Semin Med Genet. 2003 Nov 15;123C(1):48-58. doi: 10.1002/ajmg.c.20013.


Family, twin, and adoption studies have been essential in defining the genetic epidemiology of bipolar disorder over the past several decades. Family studies have documented that first-degree relatives of affected individuals have an excess risk of the disorder, while twin studies (and to a lesser extent, adoption studies) suggest that genes are largely responsible for this familial aggregation. We review these studies, including the magnitude of familial risk and heritability estimates, efforts to identify familial subtypes of bipolar disorder, and the implications of family/genetic data for validating nosologic boundaries. Taken together, these studies indicate that bipolar disorder is phenotypically and genetically complex.

Publication types

  • Review

MeSH terms

  • Adoption
  • Biomarkers
  • Bipolar Disorder / genetics*
  • Bipolar Disorder / psychology
  • Genetic Predisposition to Disease
  • Humans
  • Siblings
  • Twin Studies as Topic


  • Biomarkers