Darwin A. Guevarra, Ph.D.
Postdoctoral Fellow
Michigan State University

PainRelief.com:  What is the background for this study?  What are the main findings?

Response: Placebos are these inactive treatments that often work because people believe they are taking a real treatment. For the most part, they have real beneficial effects. However, there’s a utility-ethical issue when it comes to placebos. On one hand, they reliably work in managing daily nonclinical nuisance like emotional distress and even a host of clinical ailments like pain and depression. But, it seems like you have to lie to people that they’re taking a real treatment in order to get placebos to work. As it turns out though, there’s over a dozen studies showing that placebos can still work even when people are fully aware they are taking them. These studies educate participants about the placebo effects, how they work, and how they can probably still work even when people know they are taking one. This really opens up the possibility of ethically harnessing the beneficial effects of placebos. But there’s one glaring issue. These studies that found positive effects of non-deceptive placebos only show it with self-report and no studies show beneficial effects on biological measures. This casts some doubt on whether these self-reported beneficial effects are real.

Our study wanted to test if we can observe non-deceptive placebo effects on objective biological markers. In this case, we used a neural measure called the late positive potential that can track emotional distress. We find that non-deceptive placebos do reduce self-reported, but more importantly, neural measures of emotional distress.