From The Skeptics Dictionary
Research has…shown that the nocebo effect can reverse the body’s response to true medical treatment from positive to negative. (Root-Bernstein 1998)
A nocebo (Latin for “I will harm”) is something that should be ineffective but which causes symptoms of ill health. A nocebo effect is an ill effect caused by the suggestion or belief that something is harmful. The term ‘nocebo’ became popular in the 1990s. Prior to that, both pleasant and harmful effects thought to be due to the power of suggestion were usually referred to as being due to the placebo effect.
Because of ethical concerns, nocebos are not commonly used in medical practice or research. Thus, it is not unexpected that the nocebo effect is not well-established in the scientific literature. However, there are some anecdotes and some studies that are commonly appealed to in the literature to support its validity.
More than two-thirds of 34 college students developed headaches when told that a non-existent electrical current passing through their heads could produce a headache.
“Japanese researchers tested 57 high school boys for their sensitivity to allergens. The boys filled out questionnaires about past experiences with plants, including lacquer trees, which can cause itchy rashes much as poison oak and poison ivy do. Boys who reported having severe reactions to the poisonous trees were blindfolded. Researchers brushed one arm with leaves from a lacquer tree but told the boys they were chestnut tree leaves. The scientists stroked the other arm with chestnut tree leaves but said the foliage came from a lacquer tree. Within minutes the arm the boys believed to have been exposed to the poisonous tree began to react, turning red and developing a bumpy, itchy rash. In most cases the arm that had contact with the actual poison did not react.” (Gardiner Morse, “The nocebo effect,” Hippocrates, November 1999, Hippocrates.com)
In the Framingham Heart Study, women who believed they are prone to heart disease were nearly four times as likely to die as women with similar risk factors who didn’t believe.* (Voelker, Rebecca. “Nocebos Contribute to a Host of Ills.” Journal of the American Medical Association 275 no. 5 (1996): 345-47. ) [Of course, one might argue that the women in both groups had good intuitions. The objective risk factors may have been the same, but subjectively the women knew their bodies better than the objective tests could reveal.]
C. K. Meador claimed that people who believe in voodoo may actually get sick and die because of their belief (“Hex Death: Voodoo Magic or Persuasion?” Southern Medical Journal 85, no. 3 (1992): 244-47).
“In one experiment, asthmatic patients breathed in a vapor that researchers told them was a chemical irritant or allergen. Nearly half of the patients experienced breathing problems, with a dozen developing full-blown attacks. They were “treated” with a substance they believed to be a bronchodilating medicine, and recovered immediately. In actuality, both the “irritant” and the “medicine” were a nebulized saltwater solution.”*
Arthur Barsky, a psychiatrist at Boston’s Brigham and Women’s Hospital, found in a recent review of the nocebo literature that patient expectation of adverse effects of treatment or of possible harmful side-effects of a drug, played a significant role in the outcome of treatment (Barsky et al. 2002).
Since patients’ beliefs and fears may be generated by just about anything they come in contact with, it may well be that many things that are unattended to by many if not most physicians, such as the color of the pills they give, the type of uniform they wear, the words they use to give the patient information, the kind of room they place a patient in for recovery, etc., may be imbued with rich meaning for the patient and have profound effects for good or for ill on their response to treatment.
