Objective: To examine the developmental trajectory of response control in boys and girls with ADHD entering adolescence
Background: Children with attention deficit hyperactivity disorder (ADHD) are at risk for a host of negative outcomes including impaired social relations, academic difficulties, criminality, and comorbid psychopathology (substance use, depression, anxiety). Many of these difficulties emerge and worsen during adolescence; therefore, it is crucial to understand the developmental trajectory of ADHD-associated changes in brain and behavior during this sensitive period. Further, there is increasing recognition that gender may be an important moderator of the clinical manifestations of ADHD, with adolescent boys showing risk-taking that is more impulsive while girls show more emotional dysregulation.
To date, few studies of ADHD have taken a longitudinal approach to examining gender-based differences in behavioral changes and brain development into adolescence. Our findings have revealed gender dimorphic patterns of ADHD-associated impairments in response control and related structural brain abnormalities. Specifically, boys, but not girls, with ADHD show impaired basic motor response control and abnormalities in premotor structure; in contrast, girls with ADHD show impaired cognitive response control (e.g., when working memory is necessary to guide response selection/inhibition) and a predominance of abnormalities in prefrontal structure. Furthermore, we find that girls, but not boys, with ADHD show abnormalities in limbic structure (the emotional nervous system) and fail to show improvements in response control with reward.
Given the known gender dimorphisms in brain development, our findings in pre-pubescent children with ADHD raise important questions: Will these gender differences in abnormal patterns of brain structure and response control persist into adolescence and are they predictive of functional outcomes (e.g., academic, executive function, affective)? To answer these questions we are using a longitudinal mixed model design, that will define and contrast developmental changes in response control and brain structure in ADHD girls and boys with that of typically-developing children, and examine the impact on adolescent mental health and behavioral outcomes. Identification of patterns of brain and behavioral development associated with risk for poor outcome in both boys and girls with ADHD shows the profound public health significance of our research.