Brain scans reveal mindfulness meditation for pain is not a placebo

Pain is a complex and multidimensional experience, shaped by factors beyond physical sensation, such as a person’s state of mind and expectations about pain. The placebo effect, the tendency for a person’s symptoms to improve in response to inactive treatment, is a well-known example of how expectations can dramatically alter a person’s experience. Mindfulness meditation, which has been used for pain management in various cultures for centuries, has long been thought to work by activating the placebo response. However, scientists have now shown that this is not the case.

A new study, published in Biological psychiatryfound that mindfulness meditation taps distinct brain mechanisms to reduce pain compared to placebo responses. The study, led by researchers at the University of California San Diego School of Medicine, used advanced brain imaging techniques to compare the pain-reducing effects of mindfulness meditation, a placebo cream, and “sham” mindfulness meditation in healthy participants.

The study found that mindfulness meditation led to a significant reduction in pain intensity and discomfort, as well as a reduction in brain activity patterns associated with pain and negative emotions. In contrast, the placebo cream only reduced the brain activity pattern associated with the placebo effect, without affecting the underlying experience of pain.

“The mind is incredibly powerful, and we’re still trying to understand how it can be harnessed for pain management,” said Fadel Zeidan, Ph.D., professor of anesthesiology and the Sanford Institute for Empathy and Compassion, Sanford. “By separating pain from self and relinquishing evaluative judgment, mindfulness meditation can directly change how we experience pain in a way that doesn’t use drugs, costs nothing, and can be done anywhere.”

The study involved 115 participants, who took part in two separate clinical trials of healthy participants, who were randomly assigned to receive four interventions: a guided mindfulness meditation, a sham mindfulness meditation that consisted only of deep breathing, a placebo cream (Vaseline) that participants were trained to believe reduced pain, and as a control, one group listened to an audiobook. The researchers applied a very painful but harmless heat stimulus to the back of the leg and scanned the participants’ brains before and after the interventions.

To analyze the participants’ brain activity patterns, the researchers used a novel approach called multivariate pattern analysis (MVPA), which uses machine learning to untangle the many complex neural mechanisms underlying the experience of pain, including those arising from specific thermal stimuli, negative emotions, and placebo-mediated pain responses. The researchers were then able to determine whether mindfulness meditation and placebo engaged similar and/or distinct brain processes.

Although both the placebo cream and simulated mindfulness meditation reduced pain, the researchers found that mindfulness meditation was significantly more effective at reducing pain compared to the placebo cream, simulated mindfulness meditation, and controls.

They also found that mindfulness-based pain relief reduced synchronization between brain areas involved in introspection, self-awareness, and emotional regulation. These parts of the brain together make up the neural pain signal (NPS), a documented pattern of brain activity thought to be common to pain in different individuals and different types of pain. In contrast, the placebo cream and simulated mindfulness meditation did not show significant changes in NPS compared to controls. Instead, these other interventions tapped entirely separate brain mechanisms with little overlap.

“It has long been thought that the placebo effect overlaps with the brain mechanisms triggered by active treatments, but these findings suggest that in the case of pain, this may not be the case,” Zeidan said. “Instead, these two brain responses are completely separate, which supports the use of mindfulness meditation as a direct intervention for chronic pain rather than as a way to trigger the placebo effect.”

In modern medicine, new therapies are generally considered effective and reliable if they are more effective than placebo. Since the current study found that mindfulness meditation is more potent than placebo and does not involve the same neurobiological processes as placebo, these findings have important implications for the development of new treatments for chronic pain. However, more research is needed to demonstrate these effects in people with chronic pain compared to healthy participants.

In the long term, the researchers hope that by understanding the different brain mechanisms underlying mindfulness meditation, they can design more effective and accessible interventions that harness the power of mindfulness to reduce pain in people with a variety of health conditions.

“Millions of people suffer from chronic pain every day, and these people can do much more to reduce their pain and improve their quality of life than we previously thought,” Zeidan said. “We are excited to continue exploring the neurobiology of mindfulness and how we can harness this ancient practice in the clinic.”

Co-authors of the study include Gabriel Riegner and Jon Dean of UC San Diego School of Medicine and Tor Wager of Dartmouth College.