Rodent models: utility for candidate gene studies in human attention-deficit hyperactivity disorder (ADHD)

Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder defined by symptoms of developmentally inappropriate inattention, impulsivity and hyperactivity. Behavioral genetic studies provide overwhelming evidence for a significant genetic role in the pathogenesis of the disorder. Rodent models have proven extremely useful in helping understand more about the genetic basis of ADHD in humans. A number of well-characterized rodent models have been proposed, consisting of inbred strains, selected lines, genetic knockouts, and transgenic animals, which have been used to inform candidate gene studies in ADHD. In addition to providing information about the dysregulation of known candidate genes, rodents are excellent tools for the identification of novel ADHD candidate genes. While not yet widely used to identify genes for ADHD-like behaviors in rodents, quantitative trait loci (QTL) mapping approaches using recombinant inbred strains, heterogeneous stock mice, and chemically mutated animals have the potential to revolutionize our understanding of the genetic basis of ADHD.