Not-So-Great Expectations: The “Nocebo” Effect

by Carole Jackson, Bottom Line Health

You’re probably well acquainted with the “placebo effect,” in which a medication or other medical intervention makes you feel better simply because you expect it will… but you may not know that this sweetly innocent power of suggestion has a dark side, too. Researchers call it the “nocebo” effect, and it operates exactly the same way but in reverse. Instead of reacting to the expectation that a treatment will solve a medical problem, the nocebo effect makes people suggestible to experiencing nasty side effects from it, such as aches, nausea, balance problems — you get the idea. So just being told that a particular drug might cause you to feel bad may bring on problems. In other words, many of us who do take drugs are running around suffering from unpleasant side effects that may well be concoctions of our minds rather than the medication!

Take the Bad with the Good

With the goal of educating all of us in this lesser-known phenomenon, I contacted Ted Kaptchuk, LAc, an acupuncturist and associate professor of medicine at Harvard Medical School, a leader in placebo and nocebo research, a field that’s attracting increased attention. Dr. Kaptchuk said that though the nocebo effect is much less widely known, it occurs in the very same types of drug tests in which the placebo effect is encountered. Some of the test subjects given sham pills end up experiencing adverse reactions, the same ones that they’ve been told they might experience if given the actual medication. For instance, if test subjects believed (falsely) that they were taking aspirin, some of them might experience nausea, vomiting, stomach pain and/or heartburn — each of which can be a side effect of real aspirin.

Interestingly, studies have shown that different parts of the brain produce the placebo and nocebo effects, Dr. Kaptchuk said, but the mechanisms are similar for both…

  • Expectation: Use of certain words, descriptions and even colors create unconscious suggestions about what responses/reactions are appropriate
  • Conditioning: A side effect experienced in the past makes one more likely to experience it in similar situations in the future
  • Anxiety: Emotional state may increase susceptibility to manifest emotional disturbance as physical symptoms
  • Selective attention: Being asked to focus on the presence or absence of symptoms makes one more likely to think the symptom is being experienced

The nocebo effect is harder to study, however. While researchers are already exploring ways to harness the placebo effect for actually treating several conditions, including irritable bowel syndrome, Dr. Kaptchuk said that it is much harder — practically and ethically — to conduct useful experiments that aim to make people feel worse.

Say No to Nocebo

Nevertheless, he said, scientists are designing nocebo research that focuses on precisely what causes it (and to what degree) and also how to prevent it. Until we know more, Dr. Kaptchuk said, we would all do well to understand that being suggestible to negative effects is real and to take several steps to limit its impact….

  • When a doctor prescribes medication for you, it may help to keep in mind that side effects can be the result of the power of suggestion as described above. For some people, just being conscious that this result can occur may help lessen or even prevent the side effects.
  • When discussing a drug with your doctor, be sure the doctor addresses each potential side effect’s typical frequency of occurrence. Aspirin, for example, can cause nausea — but it does so only rarely. By knowing that a side effect is rare, you can harness the power of suggestion by telling yourself that you are very unlikely to experience it.

That’s called the power of positive thinking!

Ted Kaptchuk, LAc, associate professor of medicine at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston.