Washington, July 25 (IANS): Even a placebo with no medical value can ease pain in research participants, finds a study.

"We're still learning a lot about the critical ingredients of placebo effects. What we think now is that they require both belief in the power of the treatment and experiences that are consistent with those beliefs," said senior author Scott Schafer from the University of Colorado Boulder.

The brain plays a key role in subjects for whom the placebo gel worked, and that more research is warranted.

"Those experiences make the brain learn to respond to the treatment as a real event. After the learning has occurred, your brain can still respond to the placebo even if you no longer believe in it," Schafer pointed out in The Journal of Pain.

For the study, the team applied a ceramic heating element to research subjects' forearms.

The team then applied what the subject thought was an analgesic gel on the affected skin that turned down the temperature.

In fact, the treatment was vaseline with blue food colouring in an official looking pharmaceutical container.

"They believed the treatment was effective in relieving pain," Schafer explained.

"After this process, they had acquired the placebo effect. We tested them with and without the treatment on medium intensity. They reported less pain with the placebo," Schafer said.

The findings may open doors to new ways to treat drug addiction or aid in pain management for children or adults who have undergone surgery and are taking strong and potentially addictive painkillers.

"We know placebos induce the release of pain-relieving substances in the brain, but we don't yet know whether this expectation-independent placebo effect is using the same or different systems," Schafer concluded.