Food and Drug Administration, World Health Organisation and Committee on Proprietary Medicinal Products have published guidelines with recommendations how to conduct clinical trials. The guidelines for the clinical evaluation of antidepressant drugs contain a great variety of recommendations how to design phase I, phase II and phase III trials. Especially the pharmaceutical industry will follow these guidelines as much as possible to make the chances to register a new chemical entity as optimal as possible. While FDA and CPMP guidelines are primarily meant to be read by representatives from the pharmaceutical industries, the WHO guidelines give mainly information for clinicians. For the psychiatrist with interest in clinical research on antidepressants it is mandatory to know about the existence of these different guidelines. Fundamental differences between the guidelines do not exist; the methodological and ethical problems concerning placebo-use and relapse-recurrence problems are especially emphasized in the CPMP-guidelines.
