Animal Models of ADHD?

To describe animals that express abnormal behaviors as a model of Attention-Deficit Hyperactivity Disorder (ADHD) implies that the abnormalities are analogous to those expressed by ADHD patients. The diagnostic features of ADHD comprise inattentiveness, impulsivity, and hyperactivity and so these behaviors are fundamental for validation of any animal model of this disorder. Several experimental interventions such as neurotoxic lesion of neonatal rats with 6-hydroxydopamine (6-OHDA), genetic alterations, or selective inbreeding of rodents have produced animals that express each of these impairments to some extent. This article appraises the validity of claims that these procedures have produced a model of ADHD, which is essential if they are to be used to investigate the underlying cause(s) of ADHD and its abnormal neurobiology.