Scientific tools, fake treatments, or triggers for psychological healing: How clinical trial participants conceptualise placebos

► At their most negative, US trial participants conceptualised placebo effects as illusory effects produced by fake treatments. ► At their most positive, placebo effects were valued and conceptualised as examples of psychological healing mechanisms. ► Negative conceptualisations of placebo effects led participants to see placebo responders as gullible. ► Information for clinical trial participants should accurately reflect current scientific knowledge about placebo effects.