Nocebo effect: what it is and how it affects people

The placebo effect is an enormously popular scientific concept that, perhaps because it is a tremendously curious phenomenon, has become part of colloquial language. For this reason, many people have an approximate vision of what it is and what its scope is.

The placebo describes a positive effect on the organism after the use of a substance whose chemical properties are really innocuous, having become known in particular for its presentation as sugar tablets "disguised" as medicine real.

Accumulated evidence suggests that for this effect they may play a fundamental role. the person's beliefs and expectations. In this sense, it is understood that the benefit is associated with internal variables whose analysis is essential to understand the individual response to the use of any drug or therapeutic procedure (regardless of its objective impact on the body).

Like many other things in the field of science, there is also an antagonist for the placebo effect: the nocebo effect. This article will deal precisely with it, highlighting the nature of a lesser known but equally interesting reality.

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The nocebo effect

The term nocebo comes from Latin. Its form uses a verbal declension in the future for the verb "nocere", and its literal translation could be "(I) will hurt". It is, therefore, a phenomenon opposite to that of placebo. This nocebo effect refers to any damage that may occur after the consumption of a substance that in reality lacks "properties" by means of which to explain it, having to resort to hypotheses in which the contribution of the aspects subjective. Such detriments are often referred to as "harmful," "undesirable," or even "dangerous."

Its description was much later than that of the placebo, finding the original references in texts of the 70s, although its definitive conceptual delimitation would have to wait until the early years of the 1970s. 80. Pioneering experiments on the subject made use of fictitious electrical currents to induce supposed "headaches". In this case, the researchers deliberately provided false information to the subjects, making them believe that they would feel such a symptom after its application. Although no shock was ever delivered, almost all of the participants reported having a headache (to some degree) after the trial.

Theoretical models to explain it resort to the role of expectations, as in the case of placebo, but also to classical conditioning and personality variables. The truth is that discovering its nature is important, because sometimes it can hinder the way in which a person adheres to pharmacological treatments that could lead to a clear improvement in their state of mind health. For this reason, there have been numerous research projects that have been articulated, during the last decade, to better understand it.

In general, we know that up to 19% of people report negative side effects from using a substance whose chemistry cannot explain them in any way. Sometimes these are legal tender drugs, for which no consequences or harm have been described in the direction indicated, but that the person expressly perceives (sometimes due to past experiences or incorrect "ideas" regarding its functioning in the organism). The effect is more common among women (30%) than men (19%).

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Why happens?

The exact mechanisms by which the nocebo effect occurs are still largely unknown., because its study often involves some kind of ethical or moral dilemma. This is so because it would mean lying to the subject about what is being administered, and specifically making him believe that he is going to voluntarily expose himself to a dangerous or harmful experimental condition. Because it is necessary for the person to believe in this effect, it would imply the acceptance of some self-injurious conditions that escape the deontological codes of the research activity.

However, today at least four variables are known to be involved in the appearance of the nocebo effect: the personal expectations, classical conditioning, personality dimensions and life experience. In this section we will delve into all of them.

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1. Expectation

The value of expectations is essential for the nocebo effect, so that what the subject anticipates experience ends up imposing itself in reality as a tangible result on their organs and tissues. It is because of that in the study of this phenomenon it is essential to offer the person information about the "symptom" that one wishes to provoke, being this false (in the sense that the substance or procedure lacks any effect on his body), but used with an explicit intention to convince the subject otherwise. It has been contrasted, especially, with algic (pain) responses.

With this, and above all resorting to an authority figure (the researcher), a solid expectation would be formed with the power to generate the suggested negative effects. For example, it is known that beliefs about the emetic effect of chemotherapy (ability to cause nausea or vomiting) are proportionally related to the occurrence of this unpleasant secundarianism

2. Classical conditioning

Classical conditioning has received much credit as one of the procedures underlying the possible development of a nocebo effect. In this particular case, it would be an association (by contingency and repetition) of an unconditioned stimulus and a neutral stimulus, the first of which has the ability to provoke a response on the organism (innate). In this way, through repetitive exposure to situations in which both occur at the same time, the originally neutral stimulus would acquire the property of a conditioned one. This means that it would start to generate effects similar to those caused by the original unconditioned stimulus.

A simple example of this type of nocebo was found in a job in which a drink was offered with lemon flavor to a group of people at the same moment in which they received a dose of chemotherapy.

The repeated presentation of this sequence finally made the lemon soda (neutral stimulus) associated with the effect secondary (nausea) of such treatment (unconditioned stimulus), so that with its isolated consumption the response of threw up. That is, the lemon would start to generate this unpleasant sensation in the absence of the treatment, thus becoming a conditioned stimulus. With this process, a nocebo effect would be acquired for innocuous drinks.

3. personality factors

It's known that some personality traits can substantially contribute to the appearance of the nocebo effect. Therefore, they would be tacit elements of mediation between what was previously reviewed (expectation and classical conditioning) and its occurrence. Regarding such dimensions, today it is known that pessimistic people (that is, who set gloomy expectations on a recurring basis) are more likely to suffer the effect nocebo. In the same way, and perhaps as a direct consequence, they do not refer to the placebo or its benefits in an equivalent way to those who are optimistic (but much less so).

Likewise, the type A personality (which alludes to a recurring feeling of urgency and competitiveness as an elementary variable in interpersonal relationships) it is also associated with a higher risk of nocebo effect, when compared to B (much more "balanced" in time and life management social). The same can be said regarding the neuroticism (tendency to worry and experience negative emotions). Thus, it is concluded that pessimism, neuroticism and attitudes that emphasize competitiveness are important to understand the phenomenon.

4. Personal experiences

Finally, a fourth explanatory factor is found in previous life experiences. The fact of having witnessed how someone suffered the adverse effects of a drug, or building the anticipation that they are going to occur after acquiring imprecise knowledge about how they work in the body, is a risk factor associated with learning. All this can be accentuated in the assumption that the original vicarious model, from which the expectation was articulated, was someone to whom we are united by an emotional bond.

Adverse experiences with respect to the health system, as a whole, also precipitate the effect nocebo (since they shape the belief that these professionals are incompetent or that they use judgments invalid). In the event that the treatment is carried out during a forced entry, against the explicit will of the person to whom it is administered, the problem is also aggravated in a notable way. This last modality is currently the subject of intense controversy, and should only be applied in the event that a potential risk to the person or to third parties is suspected.

How can it be addressed?

To avoid the appearance of the undesirable nocebo effect, it is essential to influence the variables susceptible to this, such as the expectations of the person regarding the drug or the interaction that occurs in the space of therapy. One of the general recommendations is to give adequate information and do it realistically, emphasizing the closest possible balance of benefits and harms that all drugs have. This is relevant in all intervention contexts, but more so in those that are particularly critical of the expectations that accompany them (for example chemotherapy, where there are many preconceived ideas about their effects).

It is important to offer information in the most direct and truthful way possible, promoting that the person can actively participate in the treatment they are going to receive, and that the uncertainty regarding it is minimized as much as possible. In this way, it is possible for the subject to collaborate actively in their process towards recovery or improvement, and a quality therapeutic bond is stimulated. This form of relationship has been shown to reduce the risk of the nocebo effect, and also stands as the way to increase the person's satisfaction with the care received.

In short, the objective of the professional should focus on the contextualization of the benefits and the secondary aspects of the compound to be used, in the detection and correction of erroneous preconceived ideas, in the search for an active collaboration during the decision-making process, in the adequate adjustment of expectations and in the construction of a human contact with the receiving person of attention. All of this will contribute to reducing the nocebo effect and a proportional increase in therapeutic adherence.

Bibliographic references:

• Data-Franco, J. and Berk, M. (2012). The nocebo effect: A clinicians guide. The Australian and New Zealand journal of psychiatry, 47(7), 103-118
• Kong, J. and Benedetti, F. (2014). Placebo and Nocebo Effects: An Introduction to Psychological and Biological Mechanisms. Handbook of experimental pharmacology, 225, 3-15.