In the present project, investigators aim to explore the complex gene-environment interplay in children with ADHD to identify the crucial pathophysiological pathways from genes to the brain. To achieve our objective, investigators will use multimodal neurobiological approaches to effectively resolve the four major challenges in exploring gene-environment interactions on ADHD.~investigators will use multiple levels of neurobiological approaches to identify the interactions between monoamine transporter genes and environment on ADHD, including neuropsychology, neuroimaging, and neuroactive metabolites in plasma, which will provide larger effects than clinical diagnosis.~investigators will employ correlation analyses to test for the presence of correlations between the monoamine transporter genotypes and the environmental factors.~investigators will use both categorical (diagnosis of ADHD) and dimensional (inattention and hyperactivity-impulsivity symptoms of ADHD) approaches to assess the interaction effects between monoamine transporter genes and environment.~investigators will conduct interactions with ageitems to model more accurately the effects of age, which may be non-linearly related to the neurobiological basis of ADHD.
Previous studies have demonstrated significant associations of attention-deficit hyperactivity disorder (ADHD) with monoamine transporter genes, including dopamine transporter gene (DAT1), norepinephrine transporter gene (SLC6A2), and serotonin transporter gene (SLC6A4) as well as the important role of environmental factors in the pathogenesis of ADHD. Hence, investigating how genes and environments interact with each other may contribute to the understanding of the pathophysiological mechanisms of ADHD. In this 3-year project, investigators will explore the complex gene-environment interplay in ADHD with multimodal neurobiological approaches, including neuropsychology, neuroimaging, and metabolites, in order to identify the crucial pathophysiological pathways from genes to the brain.