Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Attention-Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent, developmentally persistent, and frequently diagnosed mental health disorders, thereby depleting health resources. ADHD is also clinically and empirically diverse, making it difficult to diagnose reliably. Current research highlights greater variability in task performance at the individual level (termed Intraindividual Variability; or IIV) as a hallmark feature of the disorder. Although studies have consistently demonstrated that people with ADHD show increased IIV, the underlying processes, associated contextual factors, and systematic nature of IIV have yet to be understood. The proposed study aims to characterize IIV in adolescents with ADHD by investigating the impact of contextual factors (task difficulty, task length, and behavioral symptom incidence) on IIV. Adolescents with and without ADHD will be recruited from the Hospital for Sick Children. They will complete an implicit learning task where they are instructed to press one of four keys in response to an 'X' presented at one of four corresponding spatial locations on a screen. The task changes in difficulty throughout its course. Participants' parents will complete behavioral rating questionnaires. It is expected that IIV will increase in adolescents with ADHD on later trials of the task, when the task is more difficult, and in those adolescents who have higher ratings of behavioral symptoms. Understanding IIV in ADHD will improve the capacity of health professionals to predict, identify, and treat the disorder. Findings from this study will improve the accuracy of neuropsychological assessments of ADHD, making diagnosis more reliable. Further, knowledge that IIV is an important indicator of ADHD will guide the efficient allocation of resources to the most effective psychotherapeutic drugs and cognitive-based therapies, thus improving the health of young Canadians.