A bibliometric study of international scientific productivity in attention-deficit hyperactivity disorder covering the period 1980-2005

Abstract

Objective: We have carried out a bibliometric analysis of scientific publications related to attention-deficit hyperactivity disorder (ADHD) and its pharmacological treatment over the period 1980-2005.

Method: We selected (in EMBASE and MEDLINE databases) documents that contained in their title the descriptors attention deficit hyperactivity disorder, attention deficit disorder, ADHD and ADD. As bibliometric indicators of production and dispersion we applied Price's Law and Bradford's Law, respectively. We also calculated the national participation index (PI) and correlated it with overall PI in biomedical and health sciences, with PI in the discipline of Psychiatry and with the social-health indicators (per capita Gross Domestic Product, number of physicians and total per capita expenditure on health).

Results: We obtained 5,269 original documents (2,325 corresponded to pharmacological therapy). Our results indicate fulfilment of Price's Law, since scientific production on ADHD undergoes exponential growth (correlation coefficient r = 0.9859, vs. r = 0.9011 after linear adjustment). The most widely studied drugs are methylphenidate (1,251 documents). Division into Bradford zones yields a nucleus occupied exclusively by the Journal of the American Academy of Child and Adolescent Psychiatry (500 articles). A total of 866 different journals were employed. Twelve of the first 20 used journals have an Impact Factor > 2. The principal producer country is the United States (PI = 44.2). Only four countries, of the 20 major producers in health sciences, surpass their own PI in the field of Psychiatry (Brazil, China, Spain and the United States). The correlation between PI and total number of physicians for each country situates Canada, Australia, the United States and Israel in the top positions.

Conclusion: Productivity on ADHD has undergone exponential growth in the period 1980-2005, without evidence a saturation point.