Behavior Genetics

, Volume 42, Issue 6, pp 875–885

Bigger Families Fare Better: A Novel Method to Estimate Rater Contrast Effects in Parental Ratings on ADHD Symptoms

  • R. Pinto
  • F. Rijsdijk
  • A. C. Frazier-Wood
  • P. Asherson
  • J. Kuntsi
Original Research

DOI: 10.1007/s10519-012-9561-y

Cite this article as:
Pinto, R., Rijsdijk, F., Frazier-Wood, A.C. et al. Behav Genet (2012) 42: 875. doi:10.1007/s10519-012-9561-y

Abstract

Many twin studies on parental ratings of attention deficit hyperactivity disorder (ADHD) symptoms report low or negative DZ correlations. The observed differences in MZ and DZ variances indicate sibling contrast effects, which appear to reflect a bias in parent ratings. Knowledge of the factors that contribute to this rater contrast effect is, however, limited. Using parent-rated ADHD symptoms from the Twins’ Early Development Study and a novel application of a twin model, we explored a range of socio-demographic variables (ethnicity, socio-economic status, and family size), as potential contributors to contrast effects and their interactive effect with gender composition of twin pairs. Gender did moderate contrast effects but only in DZ opposite-sex twin pairs. Family size also showed a moderating effect on rater contrast effects, which was further modified by gender. We further observed an effect of rating scale, with the DSM-IV ADHD subscale of the Revised Conners’ Parent Rating Scale more resistant to contrast effects than shorter scales of ADHD symptoms. The improved identification of situations where the accuracy of the most common informant of childhood ADHD symptoms—parents—is compromised as a result of rater bias, might have implications for future research on ADHD.

Keywords

ADHDTwin studyContrast effectsRater bias

Supplementary material

10519_2012_9561_MOESM1_ESM.docx (14 kb)
Supplementary material 1 (DOCX 14 kb)

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • R. Pinto
    • 1
  • F. Rijsdijk
    • 1
  • A. C. Frazier-Wood
    • 1
    • 2
  • P. Asherson
    • 1
  • J. Kuntsi
    • 1
  1. 1.King’s College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of PsychiatryLondonUK
  2. 2.Division of Epidemiology, Human Genetics and Environmental SciencesThe University of Texas School of Public HealthHoustonUSA