RT Journal Article SR Electronic T1 Two concepts of therapeutic optimism JF Journal of Medical Ethics JO J Med Ethics FD BMJ Publishing Group Ltd and Institute of Medical Ethics SP 563 OP 566 DO 10.1136/jme.2010.038943 VO 37 IS 9 A1 Lynn A Jansen YR 2011 UL http://jme.bmj.com/content/37/9/563.abstract AB Researchers and ethicists have long been concerned about the expectations for direct medical benefit expressed by participants in early phase clinical trials. Early work on the issue considered the possibility that participants misunderstand the purpose of clinical research or that they are misinformed about the prospects for medical benefit from these trials. Recently, however, attention has turned to the possibility that research participants are simply expressing optimism or hope about their participation in these trials. The ethical significance of this therapeutic optimism remains unclear. This paper argues that there are two distinct phenomena that can be associated with the term ‘therapeutic optimism’—one is ethically benign and the other is potentially worrisome. Distinguishing these two phenomena is crucial for understanding the nature and ethical significance of therapeutic optimism. The failure to draw a distinction between these phenomena also helps to explain why different writers on the topic often speak past one another.