Traditional and innovative experimental and clinical trial designs and their advantages and pitfalls

Abstract

Many study designs and design variants have been developed in the past to either overcome or enhance drug–placebo differences in clinical trials or to identify and characterize placebo responders in experimental studies. They share many commonalities as well as differences that are discussed here: the role of deception and ethical restrictions, habituation effects and the control of the natural course of disease, assay sensitivity testing and effective blinding, acceptability and motivation of patients and volunteers, and the development of individualized medicine. These are fostered by two opposite strategies: utilizing the beneficial aspects of the placebo response—and avoiding its negative counterpart, the nocebo effect—in medical routine for the benefit of patients, and minimizing—by controlling—the negative aspects of the placebo effect during drug development.