Being a “tough-cookie” could get you further in life than most people think, for example, you may be able to reap the benefits of pain relief from a placebo pill, according to new neuroscience research led by the University of Michigan.
The new research shows it isn’t just your mind telling you the fake drug is working or not. Depending on your personality, the brain’s personal painkiller chemicals can respond to the pain differently. For instance, if you are a more angry, hostile type, a placebo probably won’t do much for you.
These findings are the first to identify specific links between established personality traits and a person’s likelihood to experience pain relief from placebos. Researchers also found the degree of pain relief people felt from the placebo is linked to certain personality traits, in addition to the amount of a specific chemical that is released by the brain.
The new research, published in Neuropsychopharmacology, shows that around one-quarter of placebo response was clarified by personality characteristics like altruism or anger/hostility, resiliency, and straightforwardness, as calculated by a standardized test.
These findings come from a study using several healthy participants and need to be duplicated in a larger, more diverse population in order to be verified.
If the findings are confirmed, they could help investigators who examine new drugs and other treatments, an area in which placebo reactions tend to disturb the results often making it unclear if the real therapy is effective. In the future, it may be possible to adjust their results to take into consideration the individual placebo responses of participants in the clinical trials.
The current study involved pain, however, it could also have relevance in regards to how personality impacts a patient’s response to other stress-inducing factors.
Team leader Jon-Kar Zubieta, M.D., Ph.D., the Phil Jenkins Professor of Depression in the U-M Department of Psychiatry, a professor in the Department of Radiology and a member of the Molecular and Behavioral Neuroscience Institute, says:
“We started this study not just looking at measures that might seem more obviously related to placebo responses, such as maybe impulsivity, or reward-seeking, but explored potential associations broadly without a particular hypothesis. We ended up finding that the greatest influence came from a series of factors related to individual resiliency, the capacity to withstand and overcome stressors and difficult situations. People with those factors had the greatest ability to take environmental information, the placebo, and convert it to a change in biology.”
Zubieta and his team are eager to continue research in people with depression and examine how genetics, combined with personality, can impact placebo response.
He points out that the results could also have meaning for doctor-patient relationships, for example, people who have specific personality characteristics and placebo-response inclinations may also be more likely to team up with their doctors for their treatment, and communicate about any concerns regarding their treatment response.
The research team held a study that included 50 healthy volunteers, both women and men, ranging in age from 19 to 38. Each person was given a battery of standard psychological tests to pick out the most prevalent personality traits a person has. Then, the participants laid down in a brain scanner called a positron emission tomography (PET machine).
Researchers warned the volunteers they would feel some pain from salt water injected into their jaw muscle and that a painkiller, in reality a placebo, would be injected at certain intervals.
Patients rated how much pain relief they figured they would get before the experiment started, and during the 20-minute period when participants received salt water and/or the “pain killer”. Volunteers were repeatedly asked how effective they felt the painkiller was.
The PET scanner produced images of participants’ brains letting the investigators see how much of the natural painkillers, known as endogenous opioids, were released in specific areas of each volunteer’s brain during painful or “painkiller” circumstances. Blood was drawn from several participants during the study and examined for levels of a stress-induced chemical called cortisol.
Following the tests, the authors conducted sophisticated statistical analysis to measure how personality traits impacted pain ratings, brain chemical response, and cortisol levels.
Cortisol levels did not appear to be affected by personality traits and the placebo effect, however, the endogenous opioid activation caused by the placebo, and patient-rated pain severity levels, were.
Written by Kelly Fitzgerald