The "placebo effect" is often described as events that occur when patients show improvement from treatments that contain no active ingredients. While placebos have been used to ease pain and other symptoms for centuries and are used in clinical trials as controls for testing new drug therapies, the biology underlying placebo effects has only recently been truly appreciated.
A "Perspectives" article in the July 2 issue of The New England Journal of Medicine (NEJM) proposes that placebos be more broadly considered as valuable components of medical care and important tools in relieving patients' symptoms.
"A significant body of research has resulted in a shift from thinking of placebos as just 'dummy' treatments to recognizing that placebo effects encompass numerous aspects of the health care experience and are central to medicine and patient care," said the article's coauthor Ted Kaptchuk, Director of the Program in Placebo Studies at Beth Israel Deaconess Medical Center (BIDMC) and Professor of Medicine at Harvard Medical School.
"In 2001, the New England Journal of Medicine published an important meta-analysis study that found placebo effects to be insignificant. Fourteen years later, we can say that placebo effects are at the core of what makes medicine a healing profession," he adds. "Placebos don't necessarily provide cures, but they provide relief. In medical situations in which no cure is available, supportive and attentive health care can help patients to feel better, and when effective drugs do exist, placebo effects can enhance their impact."
The authors define the placebo effect as relief of symptoms that arise from patients' overall medical encounters including responses to medical symbols (such as medical diplomas prominently displayed on the wall or words on a medication bottle) and, importantly, patient-physician interactions.
According to the authors, placebo effects can dramatically enhance the effectiveness of pharmaceutical therapies, as shown in studies of patients with irritable bowel disease and episodic migraine. In particular, they write, clinicians themselves can create a placebo effect through empathy and support. They explain that attentive health care taps into both conscious and unconscious mechanisms that shift patients' perceptions of their symptoms and illness, "part of medicine's moral imperative to relieve unnecessary suffering in a manner consistent with trust and transparency."
Over the past decade a number of key basic science discoveries -- coupled with a wide range of clinical research -- has provided compelling evidence that placebo effects are firmly rooted in neurobiology.
"Recent scientific advances have enabled us to identify a trove of neurotransmitters and detect relevant neural brain pathways as well as genetic markers that help explain the biology of the placebo effect," said Kaptchuk. At the same time, he adds, clinical studies on migraine headache, asthma, chronic pain and irritable bowel syndrome have demonstrated the important role of the placebo in helping relieve symptoms of these often debilitating conditions.
The article also notes that psychosocial factors that promote therapeutic placebo effects have the potential to cause adverse consequences, known as nocebo effects.
"Not infrequently, patients perceive side effects of medications that are actually caused by anticipation of negative effects," they write. "Therefore, finding a way to balance the need for full disclosure of potential adverse effects of drugs with the desire to avoid inducing nocebo effects is a pressing issue in health care."
"The science of placebo effects is gaining traction worldwide," said Kaptchuk. "Placebo effects occur when patients are immersed in the emotional circumstances of illness, and their brains unleash chemicals that help to modulate their symptoms and change the experience of illness. We are sometimes so busy demonstrating that a therapy is 'more than a placebo,' we forget that the effects of symbols and therapeutic encounters can be valuable in and of themselves and that these and other 'placebo effects' are foundational to medicine as a healing profession."
Beth Israel Deaconess Medical Center