Rodent models of attention-deficit/hyperactivity disorder

An ideal animal model should be similar to the disorder it models in terms of etiology, biochemistry, sympatamology, and treatment. Animal models provide several advantages over the clinical research: simpler nervous systems, easily interpreted behaviours, genetic homogeneity, easily controlled environment, and a greater variety of interventions. Attention-deficit/hyperactivity disorder (ADHD) a neurobehavioural disorder of childhood onset that is characterized by inattentiveness, hyperactivity, and impulsiveness. Its diagnosis is behaviourally based; therefore, the validation of an ADHD model must be based in behaviour. An ADHD model must mimic the fundamental behavioural characteristics of ADHD (face validity), conform to a theorethical rationale for ADHD (construct validity), and predict aspects of ADHD behaviour, genetics, and neurobiology previously uncharted in clinical settings (predictive validity). Spontaneously hypertensive rats (SHR) fulfill many of the validation criteria and compare well with clinical cases of ADHD. Poor performers in the five-choice serial reaction time task and naples high-excitability rats (NHE) are useful models for attention-deficit disorder. Other animal models either focus on the less important symptom of hyperactivity and might be of limited value in ADHD research or are produced in ways that would not lead to a clinical diagnosis of ADHD in humans, even if ADHD-like behaviour is displayed.