The Nocebo Effect: From Voodoo to Clinical Trials

Author’s note: This article is summarized from various sources and attributions are linked within.

bottle of pills which may or may not work depending on your expectationsPhoto byAlexander GreyonUnsplash

Most people have heard of a placebo, when a person experiences improvement or cure of symptoms or a disease by believing the medicine they are taking is real, even if it’s just a fake pill and not true medicine. This works by the “underlying belief of the patient that the treatment they are receiving will bring beneficial effects.” This can also be accomplished through prayer, meditation, or other methods where the user truly believes something will work, despite no actual medicine being administered.

Nocebo is the opposite effect which is not discussed as much. The nocebo effect is the opposite, where “the patient’s expected outcomes can manifest real symptoms. Often, the nocebo effect is observed when patients are told potential side-effects of a drug, but are only given the placebo.”

From the Latin, nocebo means “I shall harm,” as opposed to placebo’s definition of “I shall please.”

For both the effects, the cause is that the body reacts to what it expects. In the case of nocebo, “a patient’s expectations can be just as damaging as real chemicals which are introduced to the body. This has been documented in a number of clinical trials, and the nocebo effect itself can introduce a wide array of symptoms, or even increase the symptoms already present.”

With the plethora of TV ads centered around medicine, all listing dangerous side effects, it’s not surprising that users will experience those side effects. “The nocebo effect, while still present and active in those that took a real medicine, cannot be distinguished from real side effects. In the patients who took a placebo, or fake pill, any side effects seen were caused only by the patient’s mind, as they didn’t take any medicine.”

Studies have shown, “telling someone on a certain medication that it can have negative effects will help manifest those symptoms. A serious concern includes inducing nocebo effects in a patient who normally had no side-effects.”

These effects can include “rashes to pain to changes in body chemistry.” If the patient has an expectation to feel side effects or the treatment to fail, “the success rate of that procedure drops tremendously.”

It should be noted that nocebo is not limited to treatment or pills. Suggesting someone has or will have pain can cause it to occur. One of the strongest demonstrations of this is Voodoo where the “cursed” die or feel negative effects from belief that they will.

Doctors can unintentionally cause a nocebo effect when diagnosing patients. “The impact of the delivery of a prognosis…is a blow so terrible that they (patients) are quite unable to adjust to it, and they die rapidly before the malignancy seems to have developed enough to cause death. This problem of self-willed death is in some ways analogous to the death produced in primitive peoples by witchcraft.”