Placebos elicit genuine psychobiological effects when patients believe them
Placebo drugs can still work if the patient believes it will help, observed researchers who were conducting a new study at Michigan State University (MSU). They suggest “honest” or non-deceptive placebos could have a role in modern clinical practice.
The researchers devised an experiment to test whether a non-deceptive placebo had any effects on emotional distress. Subjects were exposed to a series of either neutral or negative images and a neural biomarker called late positive potential (LPP) was measured: participants in the non-deceptive group were asked to inhale a saline-based nasal spray and informed the nasal spray was a placebo, but would help reduce their negative emotional reactions to viewing distressing images if they believed it would; participants in the control group were also asked to inhale the same nasal spray, however, they were told that its purpose was to improve the clarity of the physiological readings recorded in the study.
The results revealed subjects in the non-deceptive placebo group showed greater decreases in LPP measurements compared to the control group – the first evidence that a non-deceptive placebo can influence an objective neural biomarker of emotional distress.
“These findings provide initial support that non-deceptive placebos are not merely a product of response bias – telling the experimenter what they want to hear – but represent genuine psychobiological effects,” said MSU psychology professor Ethan Kross.
More research will be needed to determine the condition for this kind of treatment, but scientists believe non-deceptive placebos could soon be used in routine practice – most importantly, the patients receiving placebos would need to be very clearly informed they are receiving an inactive medication to make sure the practice is ethical.
