Imaging the influence and interaction of genes and stimulant medication on attention in Attention Deficit Hyperactivity Disorder (ADHD).

Attention deficit hyperactivity disorder (ADHD) is a common behavioural disorder of childhood with negative adult outcomes. The disorder is characterised by problems of attention, impulsivity (e.g., acting without thinking) and hyperactivity (e.g., being constantly on the go). The disorder appears to be strongly genetic with the most likely situation being one in which many genes each contribute a small amount of risk for the disorder. ADHD is also associated with a range of cognitive problems (i.e., problems of concentrating, planning etc). This project takes an imaging genetics approach, using functional MRI to understand the functional effects for brain and cognition of a genetic risk factor for ADHD- the dopamine transporter gene (DAT1) - which we have previously shown to influence attention. It is also well-established that not all children with ADHD achieve equal benefit from stimulant medications, such as methylphenidate (MPH), either in terms of behavioural, cognitive or academic outcomes. We will therefore examine the interaction of DAT1 genotype and MPH treatment on the neural correlates of spatial attention using fMRI. This project will help to elucidate the neurobiological mechanisms of ADHD.