Placebo-controlled trials are the recognized standard for demonstrating the efficacy of clinical and pharmacological treatments so it is significant to proponents of mindfulness meditation that it reduced pain more effectively than placebo.
The paper Journal of Neuroscience says that study participants who practiced mindfulness meditation reported greater pain relief than placebo. The study used a two-pronged approach - pain ratings and brain imaging - to determine whether mindfulness meditation is merely a placebo effect. Seventy-five healthy, pain-free participants were randomly assigned to one of four groups: mindfulness meditation, placebo meditation ("sham" meditation), placebo analgesic cream (petroleum jelly) or control.
Pain was induced by using a thermal probe to heat a small area of the participants' skin to 49 degrees Centigrade (120.2 degrees Fahrenheit), a level of heat most people find very painful. Study participants then rated pain intensity (physical sensation) and pain unpleasantness (emotional response). The participants' brains were scanned with arterial spin labeling magnetic resonance imaging (ASL MRI) before and after their respective four-day group interventions.
The mindfulness meditation group reported that pain intensity was reduced by 27 percent and by 44 percent for the emotional aspect of pain. In contrast, the placebo cream reduced the sensation of pain by 11 percent and emotional aspect of pain by 13 percent.
The authors believe mindfulness meditation reduced pain by activating brain regions (orbitofrontal and anterior cingulate cortex) associated with the self-control of pain while the placebo cream lowered pain by reducing brain activity in pain-processing areas (secondary somatosensory cortex).
Another brain region, the thalamus, was deactivated during mindfulness meditation, but was activated during all other conditions. This brain region serves as a gateway that determines if sensory information is allowed to reach higher brain centers. By deactivating this area, mindfulness meditation may have caused signals about pain to simply fade away, Zeidan said.
Mindfulness meditation also was significantly better at reducing pain intensity and pain unpleasantness than the placebo meditation, according to Fadel Zeidan, Ph.D., assistant professor of neurobiology and anatomy at Wake Forest Baptist and lead investigator of the study. The placebo-meditation group had relatively small decreases in pain intensity (9 percent) and pain unpleasantness (24 percent). The study findings suggest that placebo meditation may have reduced pain through a relaxation effect that was associated with slower breathing.