Receiving the therapy: the activation of expectation and placebo mechanisms

Fabrizio Benedetti

in The Patient's Brain

Published on behalf of Oxford University Press

Published in print October 2010 | ISBN: 9780199579518
Published online February 2013 | e-ISBN: 9780191754661 | DOI:
Receiving the therapy: the activation of expectation and placebo mechanisms

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1) This chapter aims to elucidate the effects of the ritual of the therapeutic act on the patient's brain. The term ‘therapeutic act’ is meant to include all sensory and social stimuli that surround a therapy and that let the patient know that a treatment is being administered. In addition, all the patient's internal psychological states, such as expectations and beliefs, contribute to these effects. Therefore, the therapeutic act itself is not the specific effect of a medical treatment but rather the context that is around it. 2) The study of different placebo effects across a variety of medical conditions has been crucial in understanding the role of the psychosocial context in the therapeutic outcome. There are many placebo effects, and many mechanisms can be involved. For example, when the patient expects a benefit from a therapy, his anxiety can decrease or, otherwise, reward mechanisms can be activated, whereby the reward is represented by the benefit itself. Learning and previous experience is crucial, and this may occur through both conscious expectation mechanisms and unconscious Pavlovian conditioning. 3) Understanding the biological mechanisms of placebo effects means to understand how the psychosocial context affects the patient's brain. Different social stimuli, such as the verbal suggestions of amelioration, have been found to activate a number of neurotransmitters, e.g. opioid neuropeptides, dopamine, cholecystokinin. By using neuroimaging techniques and single-cell recordings from awake patients, different regions and neuronal circuits in the patient's brain have been found to be affected by placebos, i.e. by the ritual of the therapeutic act. 4) One need not trust his doctor or believe in the treatment in order for a placebo response to occur. Totally unconscious placebo responses may take place in the immune and endocrine systems, and these are attributable to Pavlovian conditioning. Genetic subgroups of patients have also been found to respond to placebo differently, e.g. in social anxiety and major depressive disorder. 5) Knowledge about a therapy affects the therapeutic outcome. If a treatment is administered covertly (unexpectedly), with the patient unaware that a therapy is being administered, its efficacy is reduced. This indicates that expectations about the outcome are critical. Therefore, in clinical practice, all efforts should be made in order to make the patient aware of what is going on, why a procedure is being carried out and what kind of outcome should be expected. The higher efficacy of open administrations (in full view of the patient, according to routine medical practice) compared to hidden administrations of therapies (unbeknownst to the patient) should induce all health professionals to further increase their interaction with patients. Even when a treatment has to be stopped, what the therapist tells his patient is essential. The way in which treatments are delivered or interrupted plays an important role in the therapeutic outcome. 6) The concept that is emerging today is that psychosocially activated brain mechanisms are similar to those activated by drugs. In other words, social stimuli can activate some neurotransmitters in the patient's brain that bind to the same receptors to which pharmacological agents bind. Therefore, an interference between psychosocial context and drug action may take place, and this occurs on the basis of a cognitive-affective modulation of drug action. 7) All these mechanisms indicate that the ritual of the therapeutic act per se has a profound impact on the patient's brain, and every effort should be made by the clinician to enhance it. In addition, the clinician should be aware that reduced responses to a treatment may have different causes that are psychological in nature. For example, some patients respond poorly because of their weak expectations and lack of learning, although genetic factors must always be taken into consideration. 8) Understanding the biological underpinnings of the psychosocial effects on the patient's brain means to furnish scientific evidence of the intricate relationship between mental activity and different physiological functions. This should be taken into account in routine medical practice in order to avoid negative psychosocial influences on the therapeutic outcome. In fact, what we have learned today is that the response to a treatment very much depends on the psychosocial context around the patient.

Chapter.  20069 words.  Illustrated.

Subjects: Psychiatry

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