King Arthur: Now stand aside, worthy adversary.
Black Knight: ‘Tis but a scratch.
King Arthur: A scratch? Your arm’s off.
Black Knight: No it isn’t.
King Arthur: What’s that, then?
Black Knight: [after a pause] I’ve had worse.
King Arthur: You liar.
Black Knight: Come on ya pansy.King Arthur: [after Arthur's cut off both of the Black Knight's arms] Look, you stupid Bastard. You’ve got no arms left.
Black Knight: Yes I have.
King Arthur: Look!
Black Knight: It’s just a flesh wound.Monty Python and the Holy Grail
I am, I think, in a minority on this blog, in that I do not think there is a placebo effect. Period. None. Zip. Zero. Nada. Zilch.
For analysis purposes, I divide the lack of placebo effect into outcomes that do not occur with objective measurement and those that do not occur with subjective measurement.
Why the dichotomy? Those studies where there have been an active treatment, a placebo treatment and an observation group, have demonstrated no difference between observation and placebo (1). To summarize from the conclusion of the compelling NEJM review:
“We found little evidence in general that placebos had powerful clinical effects. Although placebos had no significant effects on objective or binary outcomes, they had possible small benefits in studies with continuous subjective outcomes and for the treatment of pain. Outside the setting of clinical trials, there is no justification for the use of placebos.”