Contribution of animal models to contemporary understanding of Attention Deficit Hyperactivity Disorder.

Attention Deficit Hyperactivity Disorder (ADHD) is a poorly understood neurodevelopmental disorder of multifactorial origin. Animal-based research has been used to investigate ADHD aetiology, pathogenesis and treatment, but the efficacy of this research for patients has not yet been systematically evaluated. However, such evaluation is important, given the resource consumption and ethical concerns incurred by animal use. Accordingly, we used the citation tracking facility within Web of Science to locate original research performed on animal models related to ADHD, prior to 2010. Human medical papers citing those animal studies were carefully analyzed by two independent raters to evaluate the contribution of the animal to the human studies. 211 publications describing relevant animal studies were located. Approximately half (3,342) of their 6,406 citations were by other animal studies. 446 human medical papers cited 121 of these 211 animal studies, a total of 500 times. 254 of these 446 papers were human studies of ADHD. However, only eight animal papers (cited 10 times) were relevant to the hypothesis of the human medical study in question. Three of these eight papers described results from both human and animal studies, but their citations solely referred to the human data. Five animal research papers were relevant to the hypotheses of the applicable human medical papers. Citation analysis indicates that animal research has contributed very little to contemporary understanding of ADHD. To ensure optimal allocation of Research & Development funds targeting this disease the contribution of other research methods should be similarly evaluated.