Psychotropic drug epidemiology: the road travelled, the road ahead.

Psychotropic drug epidemiology is a discipline developed to study the use and the effects of drugs in large numbers of individuals. It describes how drugs are prescribed and utilized, investigates reasons underlying prescriptions, and monitors outcomes and variables which may affect these outcomes. In this article the main purposes, study designs and limitations of current pharmacoepidemiological approaches are reviewed with the aim of assessing whether this discipline can constitute a permanent link between the experimental world of clinical trials and the real world of everyday prescribing. We support the notion that evidence generated in clinical practice, by means of pharmacoepidemiological studies, should increasingly be used to develop and suggest innovative research hypotheses to be subsequently tested in pragmatic experimental studies.