Nocebo effect

The nocebo effect, or response, is a placebo effect in the opposite direction. For example, administration of an inert substance along with verbal suggestions of pain... 

If the chemical-imbalance theory is wrong, and if depression is not a brain disease, how is it produced and how can it be prevented and treated One way to look for clues is to examine the process by which we were misled into the realm of chemistry. There is a culprit hiding in the history of the chemical-imbalance theory - a culprit that is guilty of leading doctors and patients astray over and over again in the history of medicine. The culprit is the placebo effect, and its darker twin, the nocebo effect. Depressed people got better when given MAO and reuptake inhibitors as antidepressants, and this led researchers to conclude that depression must be caused by a chemical deficiency. But much (if not all) of that improvement turns out to be a placebo effect. So to understand depression and how it might be treated effectively, we need to examine the placebo effect more carefully. That is the topic of the next two chapters. 

As 1 will discuss in greater detail in the next chapter, placebo and nocebo effects are part of a broader phenomenon - the tendency for people to experience what they expect to experience.55 Is it possible that negative expectancies can make people depressed If so, it would help explain the powerful effect of placebos in the treatment of depression, and it would also point the way to understanding how to optimize treatment in clinical settings. 

The evidence I have reviewed in this chapter indicates that placebos work for a wide variety of conditions. They can produce both positive and negative effects. They affect the body as well as the mind. They can be as strong as potent medications, and their effects can be lasting. We have also seen that placebos can produce negative effects. Furthermore, the nocebo effect maybe an important factor in clinical depression - at least for some depressed people. For this reason, understanding the placebo effect is essential to understanding how to treat depression effectively. How do inert substances produce both therapeutic and detrimental effects Chapter 6 provides an answer to this question. 

If placebo effects depended completely on the therapeutic relationship and patients emotional states, it would not be possible for the same person to show placebo effects and nocebo effects at the same time. But they do. Sometimes the same person reports both therapeutic benefits and side effects from the same placebo.15 Sometimes the more negative side effects they have experienced, the better they feel. That can happen because the side effects might convince them that they have been given a potent medication. Maybe their improvement was generated by their happiness over receiving what they believe to be an effective treatment for their condition, but this certainly would not explain their experience of side effects. 

As I discussed in Chapter 5, depression is partly a nocebo effect, in the sense that it can be produced by negative expectations... 

All treatments have a psychological component, whether to please (placebo effect) or, occasionally, to vex (negative placebo or nocebo effect). 

Placebos have side-effects, too. These are ustrally digestive or psychogenic symptoms (constipation, flatulence, diarrhea, anxiety, insomnia), and may occur in 10-20 % of the cases. More frequently taken placebos cause side effects more often. The side effect of placebos is not to be confused with the nocebo effect. The nocebo effect is at work when someone, primarily because of prejudice, reports negative health effects of a substance that is known to cause no harm. The effect is very real as was demonstrated in a study of asthmatic patients. Patients were asked to inhale water vapor and several of those who believed the water vapor contained an allergen experienced a shortness of breath. 

The same substance might exert different effects on different people. This is often connected to the placebo or nocebo effect ( 3.6), but again, reality is more complex than many people prefer to admit. Trust in a medicine is very important, but trust alone does not make a medicine effective. A drag might not have the expected effect even if the patient trusts it. This phenomenon is explained by pharmacokinetic and pharmacodynamic reasons. 

P. Tyrer UK The nocebo effect—poorly known but getting stronger... 

Nocebo Effect Unpleasant or harmful effect brought about by a placebo or a medical intervention that simulates the actual procedures. 

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