A longitudinal twin study of temperament and behavior problems: Common genetic or environmental influences?

Objectives: To assess the longitudinal covariance between emotionality, activity, and sociability (EAS) temperamental traits and anxious/depressed behavior, attention problems, delinquent behavior, and aggressive behavior and to assess the significance of genetic and common environmental influences on the temperament and behavior relations. Method: Parental responses to the Child Behavior Checklist and the EAS Temperament Survey were collected from five national cohorts of Norwegian same-sex twins. The final sample consisted of 759 twin pairs aged 7 through 17 at 2-year follow-up. Results: High emotionality predicted anxious/depressed behavior, attention problems, delinquent behavior, and aggressive behavior. The influence on delinquent and aggressive behavior was stronger in boys. Aggressive behavior was further predicted by high activity scores, especially in younger children. Significant genetic influence was found for the covariance between emotionality and attention problems and emotionality and aggressive behavior. Conclusion: Emotionality was the strongest temperamental predictor of behavior problems. The mechanisms involved in the associations between temperament and behavior problems appeared to differ with kind of behavior problems.