Use of Placebo in Clinical Trials of Psychotropic Medication

Expert consensus recommendations on the use of randomized clinical trials for drug approval in psychiatry- comparing trial designs

The use of randomized clinical trials, in particular placebo-controlled trials, for drug approval, is the subject of long-standing debate in the scientific community and beyond. This study offers consensus recommendations from clinical and academic experts to guide the selection of clinical trial design in psychiatry. Forty-one highly cited clinical psychiatrists and/or researchers participated in a Delphi survey. Consensus statements were developed based on the findings of a published, peer-reviewed systematic review. Participants evaluated statements in two survey rounds, following the Delphi method. The expert panel achieved consensus on 7 of 21 recommendations regarding the use of randomized clinical trials. The endorsed recommendations were: (i) Results from placebo-controlled trials are the most reliable and (ii) are necessary despite the growing placebo-effect; (iii) it is ethical to enroll patients in placebo-arms when established treatment is available, if there is no evidence of increased health risk; (iv) There is a need to approve new drugs with the same efficacy as existing treatments, but with different side-effect profiles; (v) Non-inferiority trials incur an increased risk of approving ineffective medications; (vi) The risk of approving an ineffective drug justifies trial designs that incur higher costs, and (vii) superiority trials incur the risk of rejecting potentially efficacious treatments. The endorsed recommendations inform the choice of trial-design appropriate for approval of psychopharmacological drugs. The recommendations strongly support the use of randomized clinical trials in general, and the use of placebo-controlled trials in particular.

Placebo-To be or not to be? Are there really alternatives to placebo-controlled trials?

Recent success of established treatment has driven concerns about the ethics of using placebo-controlled trials in psychiatry. Active-controlled (superiority or non-inferiority) trials do not include a placebo-arm and thus avoid the associated ethical concerns but show disadvantages in other respects. The aim of this paper is to review the available literature and critically discuss the evidence regarding the use of placebo-controlled- versus active-controlled trials. A MEDLINE/PubMed and Google Scholar search was performed. Studies included focused on the deliberation on placebo-controlled- versus active-controlled trials. Twenty-six studies were included. The most cited benefits of placebo-controlled trials were greater scientific reliability of the results and no average impact on patients' health. Disadvantages were mainly related to withholding effective treatment and limited generalizability. The most frequent argument in favor of active-controlled trials is the lower chance of receiving ineffective medication during the trial. Downsides include larger sample sizes, higher costs and lower scientific reliability of results. Most authors agree that all trial designs are relevant to psychiatric research depending on study goals. Whatsoever, data does not support forgoing placebo-controlled trials. Expert consensus is warranted to permit drawing conclusions on the debate on the relevance of placebo-controlled trials.