title: Disclosing the potential impact of placebo controls in antidepressant trials.
abstract: BACKGROUND
  Although placebo-control clinical trials that withhold effective treatments can be permissible, how best to inform participants of the placebo design has received little attention.
  
  
  OBJECTIVE
  To determine the effect of disclosing quantitative outcome estimates of individual treatmentv. entering placebo-control randomised control trial (RCT) on willingness to enrol in such an RCT.
  
  
  METHODS
  We randomised 278 adult patients at a depression clinic to receive standard disclosure (n= 129) or enhanced (n= 149) quantitative outcome estimates (based on decision analysis) of individual treatmentv. RCT, and assessed their willingness to enrol in the RCT.
  
  
  RESULTS
  A greater proportion of those in the standard arm preferred enrolling in RCT (41.3%v. 23.8%,P= 0.002). Those in the standard arm preferred RCT more for direct benefit than altruism reasons, whereas the opposite was true in the enhanced arm.
  
  
  CONCLUSIONS
  Disclosing the quantitative outcome implications of placebos may select for fewer but more altruistic participants.
  
  
  BACKGROUND
  S.Y.H.K. was a DSMB member of a clinical trial sponsored by Hoffman-LaRoche and he receives royalties from Oxford University Press for his bookEvaluation of Capacity to Consent to Treatment and Research. C.M. has served in the past year on a scientific advisory board and as a consultant for Janssen Pharmaceuticals.
  This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.
authors.affiliation: , BA, Department of Bioethics, Clinical Center, National Institutes of Health, Bethesda.
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Chen
authors.affiliation: , MD, PhD, Department of Psychiatry, University of Cincinnati, Cincinnati.
authors.forename: Cheryl
authors.initials: C
authors.lastname: McCullumsmith
authors.affiliation: , MD, PhD, Department of Bioethics, Clinical Center, National Institutes of Health, Bethesda and Department of Psychiatry, University of Michigan, Ann Arbor.
authors.forename: Scott Y H
authors.initials: SY
authors.lastname: Kim