title: Genetic and environmental stability in attention problems across the lifespan: evidence from the Netherlands twin register.
abstract: OBJECTIVE
  To review findings on attention-deficit/hyperactivity disorder and attention problems (AP) in children, adolescents, and adults, as established in the database of the Netherlands Twin Register and increase the understanding of stability in AP across the lifespan as a function of genetic and environmental influences.
  
  
  METHODS
  A longitudinal model was fitted on Netherlands Twin Register AP scores from 44,607 child (<12-year-old), adolescent (12- to 18-year-old), and adult (>18-year-old) twins.
  
  
  RESULTS
  Mean AP showed a downward trend with age. Age-to-age correlations ranged from 0.33 (50-≥60 years old) to 0.73 (10-12 years old). Stability in individual differences in AP was due to genetic and environmental factors, and change was due primarily to environmental factors. Nonadditive genetic influences were present from childhood to adulthood. Total genetic variance decreased slightly throughout aging, whereas environmental variance increased substantially with the switch from maternal to self-ratings at 12 years of age. As a result, heritability coefficients decreased from 0.70 to 0.74 in childhood (maternal ratings) to 0.51 to 0.56 in adolescence (self-ratings), and 0.40 to 0.54 in adulthood (self-ratings). In childhood, male subjects scored higher than female subjects. After the rater switch at 12 years of age, female subjects tended to score higher than male subjects.
  
  
  CONCLUSIONS
  Stability of AP is the result of genetic and environmental stability. The decrease in estimated heritability at 12 years of age is due to an increase in occasion-specific environmental variance and likely reflects a methodologic effect. Because environmental influences have lasting effects on AP, their early detection is crucial.
authors.affiliation: Vrije Universiteit, Amsterdam, the Netherlands. k.j.kan@vu.nl
authors.forename: Kees-Jan
authors.initials: KJ
authors.lastname: Kan
authors.forename: Conor V
authors.initials: CV
authors.lastname: Dolan
authors.forename: Michel G
authors.initials: MG
authors.lastname: Nivard
authors.forename: Christel M
authors.initials: CM
authors.lastname: Middeldorp
authors.forename: Catharina E M
authors.initials: CE
authors.lastname: van Beijsterveldt
authors.forename: Gonneke
authors.initials: G
authors.lastname: Willemsen
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology*; D005260:Female; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007206:Individuality; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D009426:Netherlands