The belief that a treatment cannot or will not work can be so strong that it can lead to worsening of symptoms, according to a recent study carried out at the University of Hamburg Medical Centre
The research, published in the journal Science Translational Medicine, found participants’ pain levels fluctuated when told they were or were not receiving remifentanil, a powerful painkiller.
When participants were told that remifentanil had been discontinued, their pain levels shot up despite the fact the treatment and dosage had remained unchanged.
These observations have given credence to the theory of a nocebo effect.
The placebo effect is not a new concept to scientists. The phenomenon of an inert substance resulting in improvement in a medical condition is a complex one. It arises from a mixture of expectation and conditioning.
“Subliminal conditioning” brought on by positive thinking could control mechanisms involved in bodily processes. Placebos have even alleviated depression.
The Hamburg research is not the first to find the opposite of the placebo could also be true.
The Latin word nocebo means “I will harm” and, in direct contrast to the placebo effect, a patient’s low or negative expectations of a treatment can reduce its efficacy. The nocebo effect is difficult to study and although the concept has been around a while, for doctors who seek a physical cause for illness, it is a difficult one to accept.
In her study, lead researcher Dr Ulrike Bingel and her team administered remifentanil to 22 participants while monitoring their brain activity using an MRI scanner.
Brain activity increased in areas associated with pain even when remifentanil was still being administered. The volunteers believed they were no longer receiving the drug and so felt pain levels increase.
To test the nocebo effect researchers varied the administration of the drug at each stage of the experiment. The MRI scans showed brain activity and pain levels were linked to the expectation of either pain or pain relief.
Significantly, in people who were told they were receiving the painkiller, areas of the brain that make it more difficult for pain signals to be transmitted became active.
Although this experiment used only 22 volunteers, Dr Bingel believes these findings highlight the importance of considering a patient’s personality and expectations to optimise overall treatments.
Image courtesy of Ayena
Bingel, U., Wanigasekera, V., Wiech, K., Ni Mhuircheartaigh, R., Lee, M., Ploner, M., & Tracey, I. (2011). The Effect of Treatment Expectation on Drug Efficacy: Imaging the Analgesic Benefit of the Opioid Remifentanil Science Translational Medicine, 3 (70), 70-70 DOI: 10.1126/scitranslmed.3001244
Leuchter, A. (2002). Changes in Brain Function of Depressed Subjects During Treatment With Placebo American Journal of Psychiatry, 159 (1), 122-129 DOI: 10.1176/appi.ajp.159.1.122
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