LOS ANGELES—Psychosocial stimuli such as therapeutic medical rituals, verbal suggestions, and the characteristics of the therapeutic setting activate the same biochemical pathways as drugs that are given in routine clinical practice. This neurobiologic effect, known as the placebo response, suggests that psychologic factors may interfere with pharmacologic agents, said Fabrizio Benedetti, MD, at the 54th Annual Scientific Meeting of the American Headache Society.
Therapeutic rituals can include taking a pill, receiving an injection, and undergoing surgery, as well as practices associated with complementary and alternative medicine. Numerous biologic mechanisms are connected to these rituals, noted Dr. Benedetti, Professor of Neurophysiology and Human Physiology at the University of Turin Medical School in Italy. “There is not a single placebo response,” he said. “Actually, there are many placebo responses across many therapeutic interventions across different medical conditions.”
Placebo Mechanisms in Pain
Researchers frequently study pain when investigating the placebo response. Dr. Benedetti cited the example of a woman who experienced limited range of movement due to pain following thoracotomy surgery. When she was given a sugar pill along with a verbal suggestion of a decrease in pain, the limitation to the range of movement disappeared, demonstrating placebo analgesia.
“When we study the placebo response, we study what happens in a patient’s brain after the presentation of all these rituals in clinical and medical practice,” Dr. Benedetti told Neurology Reviews.