title: Genetic and environmental influences on the relationship between adult ADHD symptoms and self-reported problem drinking in 6024 Dutch twins.
abstract: BACKGROUND
  Cross-sectional and longitudinal studies have shown a positive association between attention deficit hyperactivity disorder (ADHD) and problematic alcohol use in adults. To what extent this association is explained by genetic and environmental factors is largely unknown.
  
  
  METHODS
  Data on ADHD and alcohol consumption were collected by self-report in 6024 adult Dutch twins. ADHD symptoms were assessed by three subscales of the Conners' Adult ADHD Rating Scales - Self-Report: Screening Version (CAARS-S:SV): inattentiveness, hyperactivity and the ADHD index (ADHD-I). Problem drinking was defined as at least two self-reported alcohol-related problems on the CAGE questionnaire. Structural equation modelling was applied to the bivariate twin data to estimate genetic and environmental influences.
  
  
  RESULTS
  Heritability of ADHD symptoms ranged between 32% and 40% and heritability of problem drinking was 50%. The positive correlation between ADHD symptoms and problem drinking was confirmed in this general population sample, with phenotypic correlations between 0.20 and 0.28 and genetic correlations between 0.39 and 0.50. Phenotypic correlations are primarily (61-100%) explained by genetic influences with non-shared environmental influences explaining the remaining covariance. No significant quantitative or qualitative gender differences in covariance structure were found.
  
  
  CONCLUSIONS
  This study convincingly shows that ADHD symptoms and problem drinking are moderately but significantly correlated in adults and that genetic correlations are primarily underlying this association. This suggests that early interventions are required to prevent adolescents with ADHD from developing problematic levels of alcohol use. Furthermore, clinicians who treat alcohol-dependent patients should be aware that the patient may have a co-morbid condition of ADHD; integrated interventions are required.
authors: Department of Psychiatry,Academic Medical Centre,The Netherlands.
authors: E M
authors: EM
authors: Derks
authors: Department of Biological Psychology, The Netherlands Twin Register,VU University Amsterdam,The Netherlands.
authors: J M
authors: JM
authors: Vink
authors: Department of Biological Psychology, The Netherlands Twin Register,VU University Amsterdam,The Netherlands.
authors: G
authors: G
authors: Willemsen
authors: Department of Psychiatry,Academic Medical Centre,The Netherlands.
authors: W
authors: W
authors: van den Brink
authors: Department of Biological Psychology, The Netherlands Twin Register,VU University Amsterdam,The Netherlands.
authors: D I
authors: DI
authors: Boomsma
mesh_terms: D000328:Adult; D019973:Alcohol-Related Disorders / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D015897:Comorbidity; D004200:Diseases in Twins / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D057566:Self Report