Meditation Dulls Experience of Pain

Zen meditation discourages mental withdrawal from the world and dreaminess, and instead asks one to keep fully aware with a vigilant attitude. Typically one focuses on breathing and posture and aims to dismiss thoughts as they arise. Brain scans now show that Zen training leads to different activity in a set of brain regions known as the "default network," which is linked with spontaneous bursts of thought and wandering minds. Image CREDIT: Dreamstime

People who regularly meditate apparently find pain less unpleasant, because their brains are busy focusing on the present and so anticipate the pain less, blunting its emotional impact, a new study reveals.

Meditation is becoming increasingly popular as a way to treat chronic illness, such as the pain caused by arthritis. To better understand how it works, scientists recruited 12 volunteers with a diverse range of experience with meditation, spanning anywhere from no experience to decades. The kind of meditation practiced varied across individuals, but all included "mindfulness meditation," which trained them to sustain focus on the present.

Zapping participants

The researchers used a laser to zap the skin on the right forearm and induce pain in each participant. They also monitored brain activity as each participant anticipated and experienced pain.

The scientists found those with more meditation experience — up to 35 years — found the pain less unpleasant than meditators with less experience, while no corresponding age effect was seen among non-meditators.

Also, before each laser zap, brain activity suggested the more experience volunteers had meditating, the less they anticipated pain. Specifically, people who meditated showed unusual activity during anticipation of pain in part of the prefrontal cortex, a brain region known to be involved in controlling attention and thought processes when potential threats are perceived.

"The results suggest that meditation doesn't change the raw sensory experience of pain, but rather reduces the emotional response that occurs when pain is anticipated," researcher Christopher Brown, a cognitive neuroscientist at the University of Manchester in England, told LiveScience. "This in itself appears to be enough to reduce the unpleasantness of the experienced pain, even though the sensory experience is unchanged."

"Meditation trains the brain to be more present-focused and therefore to spend less time anticipating future negative events," Brown added. "This may be why meditation is effective at reducing the recurrence of depression, which makes chronic pain considerably worse."

Experiencing the raw sensation of pain can be useful — "for example, when exercising pain is useful to alert you that you might be over-exerting yourself and damaging the body," Brown explained. "Rather, it's the unpleasantness of the pain and the emotional consequences of that — for example, anxiety and depression — that need to be reduced. That's what meditation appears to selectively target."

How meditation changes the brain

It remains uncertain how meditation changes brain function over time to produce these effects.

"One might argue that if a therapy works, then why should we care how it works?" said researcher Anthony Jones, a neurorheumatologist at the University of Manchester in England. "But it may be surprising to learn that the mechanisms of action of many current therapies are largely unknown, a fact that hinders the development of new treatments. Understanding how meditation works would help improve this method of treatment and help in the development of new therapies."

"There may also be some types of patient with chronic pain who benefit more from meditation-based therapies than others," Jones added. "If we can find out the mechanism of action of meditation for reducing pain, we may be able to screen patients in the future for deficiencies in that mechanism, allowing us to target the treatment to those people."

The importance of developing new treatments for chronic pain is clear, Brown said. "Forty percent of people who suffer from chronic pain report inadequate management of their pain problem," he noted.

Unfortunately, the study doesn't conclusively prove that meditation is responsible for the reduced perception of unpleasantness and the reduced anticipation of pain. "Other factors may have influenced the results — for example, there may be already something different about people who take up a meditation practice," Brown said.

The ideal way forward would be to conduct a study in which a group of non-meditators take up meditation, "and they are monitored over a number of years to see if their perception of pain and the neural processing of pain changes," he said. "However, those studies are very challenging because of the long time periods involved — judging from our data, it could require six years before significant changes occur that are measurable. A high drop-out rate from such long-term studies would be expected."

Brown and Jones detailed their findings online May 20 in the journal Pain.

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