A new study has just come out in the journal Neuropsychopharmacology about individual differences in the placebo effect (Personality Trait Predictors of Placebo Analgesia and Neurobiological Correlates). In this study, placebo painkillers worked differently for people who had different personality traits. For people that had a hostile personality, the placebo didn’t reduce pain as much when they were injected with salt water (something that is a bit painful). Not only did it not affect their subjective ratings of pain as much, but their brains also did not produce as much opioids, the body’s natural painkiller, in response to the pain. People with other types of personalities did seem to have a biological response to the placebo.
|Sugar pill or sweet, sweet painkillers?
Maybe your body doesn’t care! Unless you’re hostile.
Photo: © Winterling | Stock Free Images
The fist thing I want to highlight is the contribution of individual differences found in these types of studies all the time. Although scientific studies often find that something seems to be true for most people, often times that thing depends on the person’s sex, age, ethnicity, personality, health status, etc. The study mentioned above is interesting because it finds that the placebo effect on pain is less effective for people with a certain kind of personality. It is important for scientists to always consider these types of individual differences in this type of work.
Another thing I want to point out about the placebo effect is that if a drug, say a painkiller, is found to not work much better than a placebo, that does not necessarily mean the drug doesn’t work at all. I think there is a common perception that if a placebo can do the same thing a drug can, then the drug is useless. This simply isn’t true. It only means that the drug can activate the same biological processes as the mind can. As we can see from this study, bodily systems in people with non-hostile personalities were activated in response to pain even when there was no drug telling their body to do this. However, we know that painkillers work, too, by activating the same biological systems. So now the question is, do painkillers also not work as well in people with hostile personalities? Or is it just placebos that do not work as well in hostile people?