Antidepressants and Placebos: Secrets, Revelations, and Unanswered Questions

We are very heartened by the thoughtful responses to our article. Unlike some of the responses to a previous meta-analysis of antidepressant drug effects ( Kirsch & Sapirstein, 1998), there is now unanimous agreement among commentators that the mean difference between response to antidepressant drugs and response to inert placebo is very small. It is so small that, despite sample sizes involving hundreds of participants, 57% of the trials funded by the pharmaceutical industry failed to show a significant difference between drug and placebo. Most of these negative data were not published (see Thase, 2002) and were accessible only by gaining access to U.S. Food and Drug Administration (FDA) documents.