Patients who don't think their medicine will help can actually limit the effectiveness of the drug.
That's according to a new study, which sheds some interesting new light on the placebo effect and may guide doctors to help patients get better results from the same medicine.
The patient's mind is one of the most important assets in medicine. Tell a person with a headache that the little green pill is an amazing new painkiller, and the patient may feel better almost as soon as she swallows the pill - even when the amazing painkiller is actually just a sugar pill.
Now, a new study takes that so-called placebo effect one step further. European researchers used a laboratory heat device to induce pain in the legs of student volunteers. Then the scientists gave them a powerful painkiller, without telling them. Researcher Irene Tracey of the University of Oxford says the students reported a slight reduction in pain.
"And then the interesting part of the experiment begins," she explains. "And that's when we then tell them, we're going to start the infusion now of the drug - of course they're already on the drug - but just the words, telling them that now the drug is coming, and the sort of kicking in of positive expectation, we get another two points pain relief on the 10-point scale, just because of the sort of positive expectation - oh great, I'm going to get this analgesic now."
Then, the researchers reversed the process, continuing the pain medicine, but telling the volunteer subjects that the pain medicine was stopping. And sure enough, they reported an increase in pain.
While all this was going on, the researchers were using a functional MRI scanner to monitor brain activity.
"And we're seeing that that brain activity is tracking that pain report. So it's coming down when they're getting the extra pain relief, and it's going all the way back up again when they have this negative expectation. So we've got the brain imaging to back up the subjective report."
In a commentary published alongside Irene Tracey's research paper, Randy Gollub of Harvard Medical School says that harnessing the patient's expectations can be used to enhance the patient's well-being.
Tracey put it this way: "Managing a patient's expectations - certainly minimizing the negative expectations - is very important if you want to get the maximum amount of efficacy, if you like, for your treatment."
But Tracey points out that doctors may have to take more time to counsel their patients - something that's always difficult to manage in today's often high-stress, fast-paced medical practice.
Irene Tracey's paper on how the placebo effect applies to actual active medication is published in the journal Science Translational Medicine.