Meditation to reduce pain is not a placebo — it's real

Mindfulness meditation, which has been used for centuries for pain management in various cultures, has long been speculated to work by activating processes supporting the placebo response — however, US scientists have now shown that this is not the case.

The placebo effect, or tendency for a person’s symptoms to improve in response to inactive treatment, is a well-known example of how expectations can significantly alter a person’s experience. But according to the new study, which was published in the journal Biological Psychiatry, mindfulness meditation engages distinct brain mechanisms to reduce pain, compared to those of the placebo response.

The study included 115 healthy participants and consisted of two separate clinical trials. Participants were randomly placed into groups to receive four interventions:

• A mindfulness meditation that was practiced by focusing on the breath without judgement
• A sham-mindfulness meditation that only consisted of deep breathing
• A placebo cream (petroleum jelly) that participants were trained to believe reduces pain
• As a control, one group listened to an audiobook
   

The researchers applied a painful but harmless heat stimulus to the back of the leg and scanned the participants’ brains while they meditated, had placebo cream applied or rested (depending on the group).

To analyse the participants’ brain activity patterns, the researchers used functional MRI and a novel approach called multivariate pattern analysis (MVPA) — developed by study co-author Dr Tor D Wager, from Dartmouth College — which uses machine learning to disentangle the many complex neural mechanisms underlying the experience of pain, including those stemming from specific heat stimulus, negative emotions and pain responses that are driven by the placebo effect. The researchers were then able to identify if mindfulness meditation and placebo engage similar and/or separate brain processes.

Although placebo cream and sham-mindfulness meditation lowered pain, the researchers found that mindfulness meditation was significantly more effective at reducing pain when compared to placebo cream, sham-mindfulness meditation, and the controls.

“It has long been assumed that the placebo effect overlaps with brain mechanisms triggered by active treatments, such as mindfulness meditation, but these results suggest that when it comes to pain, this may not be the case,” said lead investigator Dr Fadel Zeidan, from the University of California San Diego. “Instead, these two brain responses are completely distinct, which supports the use of mindfulness meditation as a direct intervention for chronic pain rather than as a way to engage the placebo effect.

“The mind is extremely powerful, and we’re still working to understand how it can be harnessed for pain management by studying the brain. By separating pain from the self and relinquishing evaluative judgment, mindfulness meditation is able to directly modify how we experience pain in a way that uses no drugs, costs nothing and can be practised anywhere.”

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

In modern medicine, new therapies are generally deemed effective and reliable if they outperform placebo. Since the present study found that mindfulness meditation is more powerful than placebo and does not engage in the same neurobiological processes as placebo, the findings have important implications for the development of new treatments for chronic pain. However, it will take more research to demonstrate these effects in people living with chronic pain as opposed to healthy participants.

In the long term, the researchers hope that by understanding the distinct 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 various health conditions.

“Millions of people are living with chronic pain every day, and there may be more these people can do to reduce their pain and improve their quality of life than we previously understood,” Zeidan concluded. “We are excited to continue exploring the neurobiology of mindfulness and how we can leverage this ancient practice in the clinic.”

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