Emotion Reactivity and Cognitive Control in Young Children with ADHD

Introduction: At school entry, young children with attention deficit hyperactivity disorder (ADHD) experience more academic and behavioral problems than children without ADHD, initiating a negative cascade of poor school adjustment and attainment (Barkley et al., 2002; DuPaul et al., 2001). The delayed development of cognitive control may underlie these school adjustment difficulties.  Researchers have postulated that poor inhibitory control and deficits in executive function impair the academic progress of young children with ADHD, and reduce their capacity to control aggressive impulses (Biederman et al., 2004; Bierman et al., 2008). While less often studied, heightened emotion reactivity is also associated with ADHD (Barkely, 1997; Foley et al., 2008). Heightened emotional reactivity may increase the cognitive load placed on the self-regulatory systems of young children with ADHD at school entry, as they must both regulate the heightened emotional arousal experienced in the social context of the school, as well as marshal their memory, attention, and problem-solving skills for academic learning. This study examined the degree to which cognitive control (inhibitory control and executive function skills) and emotional reactivity made unique contributions to the social behavior problems (aggressive-disruptiveness) and math achievement of children with ADHD entering kindergarten.
Methods: 153 kindergarteners (63% male, 76% with clinical/subclinical ADHD) participated.  Teachers and parents rated the severity of their inattention and hyperactivity symptoms. Inhibitory control was measured with a Go-No Go task, and executive functions were measured with the Head Toes Knees and Shoulders task. Emotional reactivity reflected the amount of distress children expressed when exposed to negative interpersonal events in a computer simulation. Kindergarten teachers rated aggressive-disruptive behavior, and math achievement were directly assessed.
Results: Concurrent correlations revealed that inhibitory control, executive functions, and emotional reactivity were each significantly associated with elevated aggressive-disruptive behavior and poor math achievement.  A multiple regression with aggressive behavior as the dependent variable and the severity of hyperactivity and inattention controlled revealed unique predictability for emotional reactivity, β=.14, p<.05, but not for executive function skill or inhibitory control.  A second regression with math achievement as the dependent variable and the severity of hyperactivity and inattention controlled revealed the unique predictability of executive function skills, β=.27, p<.001, but not emotional reactivity or inhibitory control.
Conclusions: Emotional reactivity and cognitive control are each implicated in the school adjustment problems of young children with ADHD, but affect different domains.