Can something as simple as falling into a trance really prevent you from feeling pain? At first glance, it seems unlikely - something as painful as surgery or childbirth should be able to break through a mere mental state. Hypnosis has, however, been reported as an effective treatment for pain mitigation in both of these situations and is quickly gaining reputability among physicians as a cheap and effective way to reduce pain perception.
In 2004, researchers at the University of Iowa Roy J. and Lucille A. Carver College of Medicine and the Technical University of Aachen, Germany, tried to identify the exact effect of hypnosis on the brain using functional magnetic resonance imaging (fMRI). fMRI measures blood flow in the brain and can be used to view activity in different regions of the brain in real time. More blood flow indicates more activity. To conduct the experiment, the researchers asked participants to first identify when a hot surface became painful to the touch (an eight on a scale from zero to ten) and used fMRI to determine where the brain sent the pain signal. They then hypnotized the subjects and gave them suggestions aimed at reducing pain while increasing the temperature on the surface to the level previously reported as painful.
All subjects reported reduced pain (less than a three on the pain scale) if they reported any pain at all. Additionally, the fMRI scan revealed a highly reduced amount of activity in the primary sensory cortex as well as the other high-level pain areas of the brain. Activity in the lower levels of the brain were unaffected by hypnosis, implying that the only changes hypnosis produced were in the conscious levels of the brain.
"The major finding from our study, which used fMRI for the first time to investigate brain activity under hypnosis for pain suppression, is that we see reduced activity in areas of the pain network and increased activity in other areas of the brain under hypnosis," said Sebastian Schulz-Stubner, M.D., Ph.D., UI assistant professor (clinical) of anesthesia and first author of the study. "The increased activity might be specific for hypnosis or might be non-specific, but it definitely does something to reduce the pain signal input into the cortical structure."
Regardless of the mechanism, the study shows that hypnosis can have a measurable effect on the brain and that it can be used in a clinical setting.
Now that there is some hard evidence of changes in brain patterns under hypnosis, Schulz-Stubner is optimistic about the future use of hypnosis: "More practically, for clinical use, it helps to dispel prejudice about hypnosis as a technique to manage pain because we can show an objective, measurable change in brain activity linked to a reduced perception of pain."