After reading the materials on placebo phenomenon, I was impressed by the fact that some people's believe of taking the "real medicine" can actually result improvement to their condition. And patients' reactions after taking the "dummy pill" can be greatly influence by the suggestions and cautions on its effectiveness given by the experimenters, just as a sugar pill may cure your headache simply because someone told you it's going to work, it may makes your symptoms worse if you were told otherwise, in other words, "thinking sick, be sick."Opposite to the placebo effect, a nocebo effect is an ill-effect caused by the suggestion or belief that something is harmful. An experiment showed that more than two-thirds of 34 college students developed headaches when told that a non-existent electrical current passing through their heads could produce a headache. In another experiment, about 20% of patients report uncomfortable side effects after taking a sugar pill in controlled clinical trials of a drug -- "and even higher percentage if they are asked."
But I fail to see whether there is enough indications in these two examples show that the ill-reactions are actually cause by the non-existent electrical current and the sugar pill. Participants' discomfort may due to other factors such as the different experiment environment, warning from experimenters, insufficient lighting, etc. Anything perceive by the participants of a study "may be imbued with rich meaning for them and have profound effects for good or for ill on their response to treatment." As an important scientific thinking principle reminds us: "Correlation Isn't Causation." In my opinion, "thinking sick, be sick" is not that simple as it may appear.
My question remained after the reading is: what measures can we take to prevent the placebo/nocebo effect from happening or minimize its influence?
"nocebo and nocebo effect", unknown author, http://www.skepdic.com/nocebo.html, Last updated on 01-Mar-2011
"The Flip Side of Placebos: The Nocebo Effect", By John Cloud
"The nocebo response" (This article was first printed in the March 2005 issue of the Harvard Mental Health Letter.)