YOU’VE HEARD OF the placebo effect? It turns out the converse may also be true.

A new study has found that patients who are told they have not been given painkillers – even when they have – believe they still feel pain. The conclusion is that this negative expectation can actually physiologically prevent the medicine or treatment from working as well as it should.

The medical researchers – including Irish researcher Dr Roisin Ni Mhuircheartaigh in the University of Oxford – used brain imaging to discover how the analgesic (painkilling) effect of a drug can be compromised depending on whether the patient expects it to work or not.

The study – The Effect of Treatment Expectation on Drug Efficacy: Imaging the Analgesic Benefit of the Opioid Remifentanil – was published yesterday in the Science Translational Medicine online magazine.

In their research, the scientists applied heat to the legs of 22 patients who then rated their pain on a scale of one to 100. They were also hooked up to an IV drip into which a painkiller could be fed without the patients’ knowledge.

The BBC reports that the tests produced fascinating results. Without a painkiller administered, patients scored their pain at 66. When the painkiller was entered into their IV streams – without their knowledge – they rated the pain at 55. But when they were TOLD that they were being given a painkiller, the pain score fell to 39.

What is most striking is when patients were told the painkiller had been taken away – when it actually hadn’t been – the average pain score went up to 64.

One of the research team at Oxford, Professor Irene Tracey, said that the painkiller used was “one of the best” available and yet the brain had been easily able to influence whether it was effective or not. She added:

Doctors need more time for consultation and to investigate the cognitive side of illness. The focus is on physiology not the mind, which can be a real roadblock to treatment.