Placebo-controlled trials in psychiatric research: an ethical perspective

The placebo-controlled trial is widely regarded as the gold standard for testing the efficacy of new treatments; however, this research design is subject to ethical controversy, especially when standard treatments of proven efficacy exist. After examining regulatory standards and ethical codes relevant to placebo-controlled trials, I offer a critique of arguments against the use of placebo control groups in psychiatric research. An absolute ethical prohibition of placebo-controlled trials in psychiatric disorders for which standard, effective treatments exist is rejected because it is based on a flawed conception of research ethics, ignores important contextual factors characteristic of psychiatric research, and could lead to the approval and use of new medications that appear equivalent in efficacy to standard treatments but may be no more effective than placebos. Four standards governing the ethical use of placebos in psychiatric clinical trials are explicated: 1) placebo-controlled trials should have scientific and clinical merit; 2) risks should be minimized and justified by the anticipated benefits of generating clinically relevant scientific knowledge and the expected benefits, if any, to individual patient volunteers; 3) patient volunteers should give informed consent; and 4) investigators should offer short-term treatment optimization to patient volunteers after completion of research participation.