Poster #200 - Inhibitory Control and Behavior Problems at Ages Two and Three: A Multimethod Twin Study

• In Event: 3-206 - Poster Session 13
  In Poster Session: PS 13 Section - Social, Emotional, Personality

Integrative Statement

In childhood, low levels of inhibitory control (IC) are associated with externalizing behavior problems and Attention Deficit Hyperactivity Disorder (ADHD). Twin studies generally show that individual differences in child IC are partly due to genetic factors. However, in early childhood, findings depend somewhat on the child’s age and the IC assessment methodology (Gagne & Saudino, 2010; 2016; Gagne & Goldsmith, 2011). For example, even though genetic influences on lab-based IC are present at age two, two studies show low or non-significant genetic influences on lab-based IC at age three. Parent-ratings of IC show a much more stable and consistent etiology and developmental trajectory from two to three. In an investigation of two-year-olds, there was fairly consistent genetic and environmental covariance between both parent- and lab-assessed IC and externalizing and ADHD behavior problems (Gagne, Saudino & Asherson, 2011). Preliminary analyses of these data at age three indicated that there was little genetic covariance between lab-based IC and behavioral maladjustment. In the current study, we investigated phenotypic and etiologic links between parent- and lab-assessed IC at age two and externalizing and ADHD behavior problems at age three in a twin sample.
Participants included 300 twin pairs (approximately half monozygotic, half female), two and three years of age, from a twin study of typically developing children. Parent-rated and lab-based assessments of IC were collected at age two and externalizing and ADHD behavior problems were rated by parents at age three. Parents completed the IC subscale on the Toddler Behavior Assessment Questionnaire-Revised (TBAQ-R) and the externalizing and ADHD-related behavior problems subscales on the Child Behavior Checklist (CBCL). Lab assessments of IC included the Dinky Toys, Gift and Snack Delay episodes of the Laboratory Temperament Assessment Battery (Lab-TAB, preschool version).
Phenotypic correlations between age two IC and age three behavior problems were significant and ranged from -.10 to -.44. Interestingly, lab-assessed IC at age two was equally correlated (externalizing behavior problems) and more highly correlated (ADHD behavior problems) with age three behavior problems than lab-assessed IC at age three was. MZ correlations exceeded DZ correlations for all traits, indicative of genetic influences. In addition, MZ cross-twin, cross-trait twin correlations between IC at age two and behavior problems at age three generally exceeded DZ correlations indicating significant genetic covariance between IC and behavioral maladjustment across age. Initial bivariate Cholesky decompositions of age 2 IC (both parent- and lab-assessed) and externalizing and ADHD behavior problems at age three, yielded significant genetic variances and genetic covariances between IC and behavioral maladjustment. Therefore, IC at age two was phenotypically and etiologically associated with externalizing and ADHD behavior problems at age three. Based on this pattern of results, we consider age two IC a genetic risk factor for behavioral maladjustment one year later. Our multimethod approach allows us to compare across age and method and has interesting developmental implications in early childhood. Namely that IC at age two shows a more consistent pattern of etiology and prediction of concurrent and later behavior problems than IC at age three.

Authors

• Jeffrey R. Gagne, Texas A&M University
  Presenting Author

• Kimberly Saudino, Boston University
  Non-Presenting Author