Medical Library
Placebo Effect? Try “Nocebo” Effect
How to identify your own pill prejudice
by Steven Brown, M.D., Ph.D.
©2008
Jennifer had a heart attack not long after her 45th birthday. Nine months and seven medication changes later, we had her blood pressure and cholesterol under perfect control. She had stopped smoking and started exercising three times a week. We had both worked hard to get her in the best possible condition.
Today, she is here for her one-year follow up visit. As I walk into the room, I am shocked as I see her lab results.
“Jennifer, what happened? Your cholesterol has doubled since last time!”
“Well, I saw this advertisement on television, and they said that the cholesterol medicine could cause muscle aches. My knee started hurting, so I stopped taking it.”
I look back at my notes from the day she came to the hospital with her heart attack. “Jennifer, do you remember the first day I met you?”
“Of course I do! I almost died that day.”
“When I asked you about your medical history that day, you told me then that you had ‘occasional knee pain.’ It looks like you have had knee pain even before you were on the medicine.”
“That’s right.”
“So, you had knee pain before you were on cholesterol medicine, and you still have it sometimes now. What makes you think the pain is from the medicine?”
“I guess I didn’t think of it like that. When I saw the ad, I just got scared and stopped the medicine.”
The Nocebo Effect
Most people have heard of the placebo effect, where a medicine gets undeserved credit when something good happens. Maybe your grandparents, like mine, wore copper bracelets to help their arthritis. Thanks to high school chemistry classes, most of us today know that copper in a bracelet will not do anything for the joints. Our grandparents felt better, perhaps because of the power of suggestion, or perhaps because their arthritis got better on its own.
The nocebo effect is just the opposite: medicine gets undeserved blame when something bad happens. In this case, Jennifer misunderstood the warnings on television. Cholesterol medications do not cause joint pain; they can cause muscle inflammation. Because of that misunderstanding, Jennifer had discarded a medicine that was dramatically reducing her chance of death.
A Common Problem
When testing a new medicine, researchers divide the study participants into two groups. One group receives the medicine, while the other receives a “placebo,” an inert substance like a sugar pill that has no effect on the disease being studied. In studies like this, 23 to 71% of people in the placebo group report negative side effects from their new “medicine. “1
Before we gloat about their lack of objectivity, we need to realize that the nocebo effect can happen to all of us. At some point during any three-day period, we all have times when we feel more fatigued than usual, develop a headache, or get drowsy at work. If we just started taking a new medicine, it is easy to blame the pill for the symptom, especially if our boss notices the drowsiness.
How can we tell the difference between the nocebo effect and true side effects?
There are some clues that can help us discern the difference between real and pseudo-side effects. First, since we take the medicine every day, side effects generally happen every day. Second, since the medicine goes all over our bodies, side effects are not ordinarily limited to one area, like the right knee. Third, if we had the same problem before, we should be reluctant to blame it on a new medicine.
In the past century, life expectancies have increased by 30 years. If we are going to take full advantage of this progress, we will have to swallow our share of pills. To do that safely, we must recognize their side effects, but we must not let pseudo-side effects keep us from their benefits. We must remember that warnings about potential side effects are not predictions about what will happen to us. The bottom line: when we develop a problem while taking a new medicine, we need to call the doctor who prescribed it. My detailed knowledge about Jennifer’s medicine, and about her history, helped guide us to the right answer. If she had been suffering from the muscle inflammation described in the commercial that sent her off-course, I could have taken the right steps to protect her from harm. Since the medicine did not cause her problem, I was able to send her to the right doctor to help with her knee pain, while still protecting her from another heart attack.
And you know what? Today, both her heart and knee are doing better than ever – thanks to the power of modern medicine.
References
1. Barsky, A., Saintfort, R., Rogers, M., & Borus, J. (2002). Nonspecific Medication Side Effects and the Nocebo Phenomenon. Journal of the American Medical Association, 287(5), 622-627.