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High Hopes Affect Placebo Benefits

By unusualsuspect     Jul 19, 2007 in Science
Researchers have found a new way to determine who will be helped by medical placebos. If your brain is turned on by the expectation of rewards in non-medical situations, you're a good candidate for a placebo.
The placebo effect is old news, but a recent study is showing the way toward determining just who can benefit from them, and how to increase that benefit. The study was conducted at the University of Michigan, using 14 volunteers who were led to believe they were taking part in two separate studies. First, the subjects were given saline shots in their jawbone and were told to expect it to be painful. They were then supposedly given either a painkiller or a placebo. Actually all of them got only the placebo. As would be expected, those who believed they had been given a painkiller reported less pain.
The interesting part is what showed up on PET scans of their brains. The subjects who believed they were on a painkiller showed much higher levels of dopamine than the other subjects. On another day, they participated in games of chance, which were supposedly the second study. fMRI brain scans while they were playing showed that those who had high expectations of winning had higher levels of dopamine. These were also the ones who reported the greatest pain relief from their "painkillers."
Jon-Kar Zubieta, senior author of the study, said "What surprised me the most was the strong link between this element of reward processing and the fact that you can predict the placebo response."
Tor Wager, a Columbia University psychologist, sees the study as an avenue that could lead to ways of increasing the placebo benefits for patients. Dopamine is involved in the brain's pleasure pathways, and if levels can be raised by raising patients' expectations of reward, then there might be less necessity for heavy use of medications. This would be particularly beneficial when drugs have serious side effects or when tolerance builds up and makes them less useful.
More about Placebo effect, Dopamine, University michigan