One of the greatest challenges confronting investigators and entrepreneurs developing new neurotech therapies has been devising a clinical trial protocol that accounts for the placebo effect. In order to fulfill requirements for a randomized control trial, neurotech device makers often devise a form of “sham” stimulation that prevents trial participants from knowing whether they’re in the treatment or control arm of a study.
The basis for this requirement seems to be a supposition that the placebo effect is a bad thing that must be eliminated from any new therapy. In fact, some clinicians have argued that the placebo effect is in and of itself a form of neuromodulation, and rather then eliminate it from treatment regimens, we should learn more about its course of action and harness its power in treating neurological and psychological disorders. We have argued in the past in this space that if there is a differential in the placebo effect between two alternative therapies, we ought not discard that differential when comparing effectiveness.
A recent study by researchers at the University of Colorado Boulder and Columbia University seems to lend support to this line of reasoning. Writing in Nature Neuroscience, they reported that learning-related brain activity in Parkinson’s patients improves as much in response to a placebo treatment as to real medication.
Past research has shown that while Parkinson’s disease is a neurological reality, the brain systems involved may also be affected by a patient’s expectations about treatment. The new study explains how the placebo treatment works in people with Parkinson’s disease by activating dopamine-rich areas in the brain. “The findings highlight the power of expectations to drive changes in the brain,” said Tor Wager, an associate professor of psychology and neuroscience at CU-Boulder and a co-author of the study. “
Parkinson’s patients have difficulty with “reward learning” because the disease kills dopamine-producing neurons. The researchers found that dopamine-rich areas of the brain associated with reward learning—the striatum and the ventromedial prefrontal cortex—became equally active when patients took either real medication or a placebo treatment.
“This finding demonstrates a link between brain dopamine, expectation, and learning,” Wager said. “Recognizing that expectation and positive emotions matter has the potential to improve the quality of life for Parkinson’s patients, and may also offer clues to how placebos may be effective in treating other types of diseases.”
We suspect that similar mechanisms may be involved with other neurological disorders such as chronic pain and mood disorders. Rather than discounting the benefits of the placebo effect, we should be looking for ways to incorporate it into new therapies.
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