Placebos in Pain Management
Throughout history, placebos have been an important part of the pharmacopoeia, but today their use in the clinical setting is considered unethical.1-3 This view remains an obstacle to a proven and effective means of endogenous pain control.4-10 Placebos may help reduce both the human and economic costs of chronic pain and their use in pain management needs to be reconsidered.
There are many definitions of “placebo” and “placebo effect” with the most common defining placebo as an inert substance or inert medical treatment and placebo effect as the response to the placebo.5 Di Blasi et al have replaced the term “placebo effect” with “context effect” and expanded the definition to include the effects the entire framework of healing has on the patient including the doctor-patient relationship.11 Benedetti elaborates stating, “…an inert medical treatment is administered within a context, and it is the context that plays the crucial role.”5
In the same vein, Moerman et al use the term, “meaning response.” The rationale being that placebos themselves are inert but what they symbolize or mean to patients can have a potent therapeutic effect. Meaning response is defined as, “…the physiologic or psychological effects of meaning in the origins or treatment of illness.”10 This definition also takes into consideration the effects the doctor-patient relationship and doctor’s words, actions and attitudes have on the patient.
Almost anything can work as a placebo and induce a placebo effect including sham medication, sham surgery, diagnostic tests, the doctor-patient relationship, and the physician’s words and attitude.1,2,5,7,8,11,14-18 Since the terms “placebo” and “placebo effect” are the most widely used, I will continue to use them—but with an amended definition to include the effects the doctor and doctor-patient relationship can have on health outcomes.
Although placebos and their effects are not well understood, there is a plethora of studies demonstrating their efficacy with the majority focusing on placebo-induced analgesia.2,4,18 There is sufficient evidence to suggest placebos activate the internal pain control processes by actuating the endogenous opiate system and other mechanisms for pain control and altering the experience of pain.4-10 This endogenous opiate effect is confirmed since naloxone has been shown to reverse placebo analgesia and PET scans have shown the same areas of the brain activated during both placebo and opioid induced analgesia.4,5,7,8,18 In one study, peak B endorphin levels within cerebrospinal fluid dramatically increased during placebo analgesia compared to non-responders. Another study reported functional magnetic resonance imaging experiments showing a decreased activity in the pain-sensitive brain regions, or pain matrix, with placebo analgesia.9,19 There is little doubt placebos can help manage pain.
Doctor-Patient Relationship Effects
Many studies have shown that the doctor-patient relationship can have a considerable impact on health outcomes and interactions between patient and doctor can trigger physiological changes within the patient.5,15,16,20 A physician’s words of assurance, positive attitude, friendliness and empathy have a positive effect on patients’ health.15,20,21 On the other hand, a physician who is negative and creates stress and fear in the patient can have a deleterious effect.5,22
A negative attitude does impact health. A study by Anda et al suggests feelings of depression and hopelessness are associated with increased risk of morbidity and mortality.23 Women in the Framingham Study who believed they had an increased risk of having a heart attack were 3.7 times more likely to die from coronary problems compared to a group of women who believed they were less likely.24
According to Di Blasi et al, “…the most powerful trigger of a self-healing response is the relationship between the patient and health professional.”11 While Engel states, “Even with the application of rational therapies, the behavior of the physician and the relationship between patient and physician powerfully influence therapeutic outcomes for better or worse.”13 The doctor-patient relationship has been neglected and needs far greater attention.3
Gregory Stock in the American Journal of Bioethics writes, “If hand-holding and sugar pills can soothe us and reduce our pain as effectively as a potent narcotic, then aren’t they the preferable treatments even if their value depends upon some mistaken belief of ours in their intrinsic efficacy?”12
The biomedical model is the predominant paradigm of disease in Western medicine and states that illness can be explained by “deviations from the norm of measurable biological (somatic) variables” with psychological and social factors being independent of disease.13 Cartesian mind-body dualism, which separates the mind from body, is an integral part of the biomedical model and may contribute to the lack of acceptance and understanding of placebo use.1,13 If the psyche has no impact on the corpus, then why take any action to assuage the mind to palliate the body? Engel suggests medicine needs a new paradigm—a biopsychosocial model which takes into consideration the impact psychological and social factors have on disease.13 If this were the dominant medical model, placebos may be accepted and used throughout medicine.
Placebos are effective and should be used in pain management as their use may decrease both the human and economic costs of chronic pain. The physician’s words and attitude, and the doctor-patient relationship can have a powerful therapeutic effect on the patient’s health and should be considered an integral part of the placebo effect. Replacing the biomedical model with the biopsychosocial model and establishing guidelines for the use of placebos may help re-establish the placebo as an integral part of medicine and healing.