Step closer to unravelling the mystery of medically unexplained pain such as chronic low back pain

Aug 9 2004

Researchers are one step closer to unravelling the mystery of medically unexplained pain such as chronic low back pain, which continues to baffle doctors.

A study exploring the experience of pain in hypnotised volunteers has found that some types of pain which cannot be traced to a medical condition may have its origins in our brains, not in our bodies.

The study by University College London and University of Pittsburgh Medical Centre found that volunteers who felt pain as a result of hypnotic suggestion showed strikingly similar brain activity to those subjected to physical pain via pulses of heat at 49 degrees Celsius.

The study, to appear in the next issue of NeuroImage, also found that when the volunteers were asked to simply imagine that they felt the same pain, they had significantly different brain activity than under hypnotised and physical pain conditions.

Dr David Oakley, Director of UCL's Hypnosis Unit, says: "The fact that hypnosis was able to induce a genuine painful experience suggests that some pain really can begin in our minds. People reporting this type of pain are not simply imagining it.”

A separate hypnosis study by Dr Oakley and UCL Professor Patrick Haggard explored the basis of free-will in hypnotised volunteers who were asked to deliberately move their finger, were told their finger would move ‘all by itself’ or had their finger moved for them.

The study, which will appear in the next issue of Consciousness and Cognition, found that volunteers under hypnosis reported that when their finger moved ‘all by itself’ it felt 'involuntary' even though they had actually moved it themselves.

Dr Oakley says: "This study questions the conscious nature of free-will, which is an important issue for society. For example, in legal terms someone may only be considered responsible for a criminal act if it is performed with conscious intention."

In both studies volunteers were chosen using the Harvard Group Scale of Hypnotic Susceptibility, where those scoring 8 or more out of 12 were selected. Volunteers were hypnotised using a simple procedure involving imagery such as going down stairs or descending in a lift.

Dr Oakley adds: “Studies such as these, published in reputable scientific journals, provide good evidence that hypnosis has moved out of the Dark Ages and is now recognised as a valuable research tool. Hypnosis offers a safe way of altering a person’s experience of themselves or of the world around them. Brain imaging is another good way of exploring these reported changes – you can't easily fool a brain scanner."