Understanding placebo effects: how rituals affect the brain and the body

In a typical prehistoric scene, say in 4000 BC, a wounded warrior is dragged to the shaman tent. The respected shaman takes a look at the wound and assures the warrior that he will be healed with the proper prayers and ritual dances. He then prepares a strong-smelling mixture of herbs and seeds, and as the whole tribe chants rhythmically around the campfire, he carefully applies it to the wound, all the while uttering incomprehensible sentences passed on to him by a venerable line of ancestral shamans.

Now let’s come to more recent times, say in 2010 AD. A wounded soldier is carried to the military hospital. The medical staff completes a physical examination. A CT scan to rule out internal lesions is carried out to the reassuring buzz of the most recent technology, and a respected clinician wearing a spotless white coat reassures the soldier that he will be healed with the proper drugs and physiotherapy.

Across the divide of millennia, what do these two pictures have in common? The ritual of the medical and therapeutic act. Shamans of the past and clinicians of today share instinctual knowledge that the context surrounding a therapy is an important part of the therapy itself. Rituals have changed and adapted to the contemporary world, but they are still here. In spite of the huge time span across human history, contexts help both ancient and modern patients to develop trust and expectation that they will eventually regain their health.

Placebo effects work in this way too. Giving a placebo consists of essentially delivering a context without the substance. It is a wrapping devoid of content. Yet, the empty box itself acts subtly on the patient’s mind, just as an active drug would do, activating or silencing synapses, altering neurotransmitter content in specific brain areas, and modifying brain activity in ways that are today amenable to scientific inquiry. Placebos are not only the archetypal sugar pills but can be anything with the power to impact on the patient’s expectations. Placebos are made of words, symbols, rituals, meanings. What is important is not really the tool used, but the changes it triggers in neural activity, and how these changes ultimately affect psychological and bodily functions.

Within this framework, today we are witnessing an epochal transition in the medical paradigm, whereby general concepts, such as suggestibility and power of mind, can now be described in terms of a true biology of placebo effects and doctor-patient interaction. Thanks to modern scientific tools, important questions have been addressed and partially answered, such as psychological and emotional influences on symptoms, diseases, and responses to therapies.

The main concept that is emerging today is that placebos, words, therapeutic rituals and patients’ expectations modulate the same biochemical pathways that are affected by the drugs used in routine medical practice. As a matter of fact, this statement should be reversed. It would be more appropriate to say that drugs use the same biochemical pathways of rituals. In fact, rituals were born long before drugs.

Rituals heal but they can also kill. Nocebo effects are the evil twins of placebo effects, the negative consequence of negative rituals and contexts that induce distrust and hopelessness. These can be triggered by a variety of contexts in non-western societies, such as voodoo, and in western society, such as exaggerated health warnings in the media. A social contagion of negative expectations can spread across people very quickly, sometimes inducing worrisome mass phenomena.

Placebo effects are all of these things. The crucial point, and indeed the big revolution, is that today we can study these phenomena, once the domain of psychology, sociology and anthropology, with the tools of the modern biomedical paradigm. These biological tools involve cellular and molecular accuracy, with rituals and contexts interpreted in terms of specific brain regions and biochemical pathways, thus eliminating the old dichotomy between biology and psychology.

Heading image courtesy of Fabrizio Benedetti. Do not use without permission.