Temperament, executive control, and attention-deficit/hyperactivity disorder across early development

Research examining factors linking early temperament and later attention-deficit/ hyperactivity disorder (ADHD) is limited by cross-sectional approaches and having the same informant rate both temperament and psychopathology. The authors used multiinformant/multimethod longitudinal data to test the hypothesis that negative emotionality during preschool is positively associated with ADHD symptom severity in middle childhood, but developing executive control mediates this relation. Children (N = 161) with and without ADHD were evaluated 3 times: parent and teacher temperament ratings and NEPSY visual attention at ages 3-4 years; Wechsler Intelligence Scale for Children-4th edition Working Memory Index and NEPSY Response Set at age 6 years; and ADHD symptoms using the Kiddie-SADS at age 7 years. Parent and teacher ratings of preschoolers' temperament were combined to form an anger/frustration composite. Similarly, an executive functioning composite was derived from age 6 measures. Bootstrapping was used to determine whether age 6 executive functioning mediated the relation between early anger/frustration and later ADHD symptom severity, while controlling for early executive functioning. Preschoolers' anger/frustration was significantly associated with later ADHD symptoms, with this relation partially mediated by age 6 executive functioning. Developing executive control mediates the relation between early anger/frustration and later ADHD symptom severity, suggesting that anger/frustration influences ADHD symptom severity through its impact on developing executive control. Early interventions targeting the harmful influences of negative emotionality or enhancing executive functioning may diminish later ADHD severity.