Main article: Nocebo
A phenomenon opposite to the placebo effect has also been observed. When an inactive substance or treatment is administered to a recipient who has an expectation of it having a negative impact, this intervention is known as a nocebo (Latin nocebo = "I shall harm"). A nocebo effect occurs when the recipient of an inert substance reports a negative effect and/or a worsening of symptoms, with the outcome resulting not from the substance itself, but from negative expectations about the treatment.
Placebos used in clinical trials have sometimes had unintended consequences. A report in the Annals of Internal Medicine that looked at details from 150 clinical trials found that certain placebos used in the trials affected the results. For example, one study on cholesterol-lowering drugs used olive oil and corn oil in the placebo pills. However, according to the report, this "may lead to an understatement of drug benefit: The monounsaturated and polyunsaturated fatty acids of these 'placebos,' and their antioxidant and anti-inflammatory effects, can reduce lipid levels and heart disease." Another example researchers reported in the study was a clinical trial of a new therapy for cancer patients suffering from anorexia. The placebo that was used included lactose. However, since cancer patients typically face a higher risk of lactose intolerance, the placebo pill might actually have caused unintended side-effects that made the experimental drug look better in comparison.
From Wikipedia, the free encyclopedia
The nocebo effect is when a negative expectation of a phenomenon causes it to have a more negative effect than it otherwise would. A nocebo effect causes the perception that the phenomenon will have a negative outcome to actively influence the result. Mental states such as beliefs, expectations and anticipation can strongly influence the outcome of: disease; experience of pain; and even success of surgery. Positive expectations regarding a treatment can result in more positive outcomes and this effect is known as the placebo effect. Both placebo and nocebo effects are presumably psychogenic but also produce measurable physiological changes as well as changes in the brain, the body and behavior. For example, when a patient anticipates a side effect of a treatment, he/she can suffer them even if the medication provided is an inert substance. One article that reviewed 31 studies on nocebo effects reported a wide range of symptoms that could manifest as nocebo effects including nausea, stomach pains, itching, bloating, depression, sleep problems, loss of appetite, sexual dysfunction and severe hypotension.
The term nocebo (Latin nocebo, "I shall harm," from noceō, "I harm") was coined by Walter Kennedy in 1961 to denote the counterpart to the use of placebo (Latin placēbō, "I shall please," from placeō, "I please"); as a substance that may produce a beneficial, healthful, pleasant, or desirable effect.
In the narrowest sense, a nocebo response occurs when a drug-trial subject's symptoms are worsened by the administration of an inert, sham, or dummy (simulator) treatment, called a placebo.
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