Attention deficit hyperactivity disorder (ADHD) is well established as a potentially debilitating neurodevelopmental disability. Its primarily genetic basis is confirmed by population genetic studies. Research has highlighted the potential importance of the dopamine transporter and receptor genes, and the genetic microsatellite synaptosome-associated protein of 25,000 daltons (SNAP-25). Intervention studies demonstrate the clinical benefits of dopaminergic agents. Brain neural circuitry activation and cerebral regional blood flow have been shown to be normalised following dopaminergic administration in individuals with ADHD.