Date of Award
12-1-2023
Degree Name
Master of Arts
Department
Psychology
First Advisor
Kibby, Michelle
Abstract
Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent neurodevelopmental disorders in childhood. Currently, the Diagnostic and Statistical Manual of Mental Disorders (DSM) categorizes the disorder within a two-dimensional frame, with ADHD-Primary Inattentive (ADHD-PI) and ADHD-Hyperactive/Impulsive (ADHD-HI) being separate dimensions/factors. There exists a debate in the literature regarding the cohesion of the ADHD-HI subtype, with some researchers postulating that hyperactivity and impulsivity should be construed as separate dimensions due to unique developmental trajectories and behavioral presentations of the two traits. Currently, there is data supporting both the separation and the continued integration of the -HI subtype from studies using factor analysis. Research is scarce on how hyperactivity and impulsivity may uniquely predict common deficits associated with the disorder. Given there exists emerging evidence for some differences between hyperactivity and impulsivity in the literature in terms of developmental trajectories, it is important to investigate potential incongruity between the two traits in other areas, such as executive functioning, because executive functioning is commonly affected in ADHD. Data from children with ADHD and typically developing controls were obtained from a pre-existing database. Both lab-administered and questionnaire measures were utilized. It was hypothesized that rule violations, inhibition, and the visual-spatial sketchpad would be uniquely related to impulsivity. The central executive was expected to be uniquely related to hyperactivity. Emotional control and an overall measure of working memory were expected to be related to both variables. Only exploratory analysis was planned for the phonological loop due to the conflicting nature of the research on it in ADHD. Confirmatory findings showed that inhibition and working memory functioning in daily life were related to both hyperactivity and impulsivity when using the total sample, although WM was more related to hyperactivity. These findings tended to be more in line with the two-dimensional frame. Exploratory findings on working memory suggest hyperactivity and impulsivity may be more dissociable, as WM was uniquely related to hyperactivity in controls, but impulsivity in ADHD. These findings could be used to support the three-dimensional approach. Future research should continue to study this debate by examining other common deficits associated with ADHD, along with continued investigation of hyperactivity and impulsivity in relation to executive functioning.
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