Volunteers from Blackpool have taken part in a remarkable TV experiment.
A group of 117 people from Blackpool were selected to take part in the experiment devised by Dr Michael Mosely for the BBC's Horizon programme.
All had chronic back pain which was seriously affecting their lives.
They include Stacey, who was struggling to keep up with her two energetic daughters, wheelchair-user Jim, who longs to be able to get back on a boat, and poker player Moyra, who was looking for a painkiller which doesn't affect her performance.
They believed they were taking part in the drug trial of a powerful new painkiller, but in fact all had been given a harmless placebo pill.
And in remarkable results, almost half of the participants reported their back pain disappearing completely.
Dr Mosley said: "People think only the weak-willed, foolish or ignorant will respond to a placebo, whereas we know none of these things are true.
"The only thing significant about the people who respond to the placebo is they tend to be people who are more open to the experience.
"There are lots of things that make pain worse, and one of them is being lonely.
"We are social creatures, so being socially isolated is one of the drivers of pain and depression. Share things, and that's likely to help. And talk about your pain."
Horizon: Can My Brain Cure My Body is available now on BBC iplayer