Placebos can reduce brain markers of emotional distress even when people know they are taking them, researchers report.
Scientists have long documented that people often feel better after taking a treatment without active ingredients simply because they believe it’s real—known as the placebo effect.
Now, evidence shows that even if people are aware that their treatment is not “real”— known as nondeceptive placebos—believing that it can heal can lead to changes in how the brain reacts to emotional information.
“Just think: What if someone took a side-effect-free
sugar pill twice a day after going through a short convincing video on the power of placebos and experienced reduced stress as a result?” said Darwin Guevarra, a postdoctoral fellow at Michigan State University and lead author of a new study in
Nature Communications. “These results raise that possibility.”
Researchers tested how effective nondeceptive placebos are for reducing emotional brain activity.
“Placebos are all about ‘mind over matter,'” said co-author Jason Moser, professor of psychology. “Nondeceptive placebos were born so that you could possibly use them in routine practice. So rather than prescribing a
host of medications to help a patient, you could give them a placebo, tell them it can help them and chances are—if they believe it can, then it will.”
To test nondeceptive placebos, the researchers showed two separate groups of people a series of emotional images across two experiments. The nondeceptive placebo group members read about placebo effects and then researchers asked them to inhale a saline solution nasal spray.
The researchers told the participants the nasal spray contained no active ingredients but would help reduce their
negative feelings if they believed it would. The comparison control group members also inhaled the same saline solution spray, but were told that the spray improved the clarity of the physiological readings the researchers were recording.
The first experiment found that the nondeceptive placebos reduced participants’ self-reported emotional distress. Importantly, the second study showed that nondeceptive placebos reduced electrical brain activity reflecting how much
distress someone feels to emotional events, and the reduction in emotional brain activity occurred within just a couple of seconds.
“These findings provide initial support that nondeceptive placebos are not merely a product of response bias—telling the experimenter what they want to hear—but represent genuine psychobiological effects,” said co-author Ethan Kross, a professor of psychology and management at the University of Michigan.
The researchers are already following up on their data with a real-life nondeceptive placebo trial for COVID-19 stress.
Additional co-authors are from Dartmouth College.
