In short, has there ever been a study where patients were given a placebo (without their knowledge, of course), and stated their expectation of whether or not they thought the treatment was going to work?
What I’m getting at is whether or not there’s a correlation between conscious belief (in the efficiency of the treatment) and the placebo effect. The naive expectation would certainly be that if you’re sure a placebo won’t work, then it actually won’t, but experience tells me that my naive expectations when it comes to human psychology are usually dead on wrong.
It seems an easy enough study to carry out (just couple it with any of the normal placebo-controlled studies – oh, it just occurred to me that the converse, whether or not expectation has an effect on effective treatments, might be just as interesting!), and I think the insights into the workings of the placebo effect might be of a certain value – so, has it ever been done?