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Positive Thinking May Make Drugs Work Better

Study Suggests Your Expectations Can Alter the Effectiveness of Pain Relievers
WebMD Health News
Reviewed by Laura J. Martin, MD

Feb. 16, 2011 -- When it comes to taking medicine, you may get what you expect.

A new study has found that your expectations can affect how well pain medications work. Being optimistic may boost their effectiveness in blocking pain, while being pessimistic may lower their effectiveness.

Unlike earlier research, the new study used brain imaging techniques to examine brain regions that are known to be associated with pain.

Scientists say that until now, little research has been done to clarify the brain mechanisms that control how different expectations affect drugs.

The study is published in the Feb. 16 issue of Science Translational Medicine.

The Power of Expectations

German and British researchers used brain scans to study how positive or negative expectations affected brain activity in a group of healthy people.

The researchers used a heat source to cause pain to the volunteers and scanned their brains while administering pain medication.

The researchers write that expectations that the pain medication would be effective doubled the effect of the drug, while a negative or gloomy outlook made the pain reliever less effective. The pain medication used was Ultiva, an IV drug generally used during surgery.

“Doctors shouldn’t underestimate the significant influence that patients’ negative expectations can have on outcome,” Irene Tracey, of Oxford University’s Center for Functional Magnetic Resonance Imaging of the Brain, says in a news release.

Twenty-two healthy volunteers took part in the study. They were given the pain medicine and placed in an MRI scanner. Heat was applied to a leg at a level sufficient for each person to rate the pain at 70 on a scale of 1 to 100. An intravenous line was used to administer the pain medication.

Unknown to the volunteers, the researchers started giving the drug to see what effects it would have in the absence of any knowledge or expectation of treatment. The average initial pain rating of 66 went down to 55.

Then the participants were told the drug would start being administered, though no change was made in the medication dose. Still, the average pain ratings dropped further, to 39.

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