The placebo effect, we know: it is a biological or psychological effect induced by a tablet, a liquid or an inactive injection, administered in pharmacology as a witness to the activity of a drug.
The nocebo effect is defined by the Larousse dictionary as the “appearance of benign adverse effects, mainly of psychological origin, following administration of an inactive drug or one that cannot itself produce these effects”.
So the nocebo effect is a bit like an unresearched placebo effect. In the case of the Covid vaccine, an American study found that three-quarters of adverse side effects were experienced only because the patient expected to experience adverse effects.
We obviously cannot speak of an inactive drug in this case. Dr. Kalpit Agnihotri, general practitioner, specifies in the journal Canadian Family Physician that the nocebo effect can also occur before “the administration of a harmless product or treatment which, when taken by a patient or given to him, is associated with harmful side effects or worsening of symptoms due to negative expectations or the psychological state of the patient”.
Conducive anxiety
On his website, the psychologist Ludovic Gadeau recalls that “the term nocebo, etymologically means “I will harm””. He argues that “one in four patients would be subject to it”.
Why ? “Anxiety would be favorable to him: having patients test a neutral product without telling them what it is, or what effects it can produce, would trigger symptoms ex nihilo in more than 80% of cases”, he continues. . This makes it possible to “become ‘addicted’ to a totally neutral product”.
According to the psychologist, “the nocebo effect, like the placebo effect, is not linked to the medicine taken, but mainly to the patient’s expectation, itself arising from the doctor’s expectation of the treatment he prescribes. For the vaccine, it is of course not a question of addiction but of the fact that patients do expect to experience adverse effects.