Which treatment is more effective: placebo one or placebo two? This is the test researchers Ted Kaptchuk and colleagues investigated in their study published in the British Medical Journal and summarized in an April 2006 issue of Discover (“Placebo vs. Placebo“). Kaptchuk looked at 266 volunteers with chronic arm pain and randomly assigned each of them to either receive a sugar pill or be subjected to pretend acupuncture.
Both groups experienced side effects to the placebos:
“25 percent of the acupuncture group experienced side effects from the nonexistent needle pricks, including 19 people who felt pain and 4 whose skin became red or swollen. 31 percent of the pill group experienced side effects from the make-believe drug, including dizziness, restlessness, rashes, headaches, nausea, and 4 cases of nightmares. Dry mouth and fatigue were the most common side effects, and 3 subjects withdrew from the study after reducing the dosage failed to control their symptoms. The reported side effects exactly matched those described by the doctors at the beginning of the study.”
After ten weeks, individuals receiving the fake acupuncture reported a larger reduction in pain than those taking the sugar pill. Kaptchuk has a logical explanation for this.
“Kaptchuk says that the rituals of medicine explain the difference: Performing acupuncture is more elaborate than prescribing medicine. Other rituals that may make patients feel better include ‘white coats, and stethoscopes that you don’t necessarily use, pictures on the wall, the way you reassure a patient, and the secretaries that sign you in.’ Careful manipulation of such rituals could make all types of treatment more effective, Kaptchuk suggests.“