title: Changes in genetic and environmental influences on trait anxiety ćfrom middle adolescence to early adulthood.
abstract: BACKGROUND
  Middle adolescence to early adulthood is an important developmental period for the emergence of anxiety. Genetically-influenced stable traits are thought to underlie internalizing psychopathology throughout development, but no studies have examined changes in genetic and environmental influences on trait anxiety during this period.
  
  
  METHODS
  A longitudinal twin study design was used to study same-sex twin pairs (485 monozygotic pairs, 271 dizygotic pairs) at three ages, 14, 18, and 21 years, to examine developmental shifts in genetic and environmental effects on trait anxiety.
  
  
  RESULTS
  The heritability of trait anxiety increased with age, particularly between ages 14 and 18, no significant new genetic influences emerged after age 14, and the genetic influences were highly correlated across the three ages, supporting developmentally stable genetic risk factors. The environmental effects shared by members of a family decreased in influence across adolescence, while the influence of environmental effects unique to each individual twin remained relatively stable over the course of development and were largely age-specific.
  
  
  CONCLUSIONS
  The twin study design does not inform about specific genes and environmental risk factors.
  
  
  CONCLUSIONS
  Genetic influences increased in importance from middle to late adolescence but common genetic factors influenced trait anxiety across the three ages. Shared environmental influences decreased in importance and demonstrated negligible influence by late adolescence/early adulthood. Nonshared environmental effects were almost entirely age-specific. These findings support the importance of developmentally-sensitive interventions that target shared environmental factors prior to middle adolescence and shifting non-shared environmental risks at each age.
authors.affiliation: Department of Psychology, Georgia State University, PO Box 5010, Atlanta, GA 30302-5010, USA.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Garcia
authors.forename: Erin C
authors.initials: EC
authors.lastname: Tully
authors.forename: Nicholas
authors.initials: N
authors.lastname: Tarantino
authors.forename: Susan
authors.initials: S
authors.lastname: South
authors.forename: William G
authors.initials: WG
authors.lastname: Iacono
authors.forename: Matt
authors.initials: M
authors.lastname: McGue
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001007:Anxiety / Q000209:etiology* / Q000235:genetics; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology; D055815:Young Adult
keywords: Adolescence; Anxiety; Environment; Genetics