Placebo washout is not a meaningful part of antidepressant drug trials.

Most trials testing the effectiveness of psychotropic drugs begin with a placebo washout phase. Hypothetically this technique rids studies of placebo responders before randomization of subjects to drug and placebo groups. In theory, this lowers the level of response to placebo in the study and magnifies the superiority of the response to medication. An analysis of 10 years of research literature demonstrates that the washout technique does not do what it was designed to do in antidepressant studies. Within placebo or drug groups neither measures of depression nor dropouts were affected by including a preliminary washout in the design. The findings are consistent with the two other studies that have addressed this issue.