Don't underestimate the placebo effect

In a number of studies on depression and anxiety, the consumption of sugar pills have frequently beat out target drugs with their positive effect on participants. Photo / Thinkstock
In a number of studies on depression and anxiety, the consumption of sugar pills have frequently beat out target drugs with their positive effect on participants. Photo / Thinkstock

That's the conclusion of international researchers who examined how scientists treated placebo medications in comparison with the "active" target drugs being tested against them in large clinical trials.

Although the word "placebo" is borrowed from Latin, meaning "I shall please," the use of inert drugs is largely regarded as a somewhat shameful deception by many modern medical practitioners.

Yet scores of recent studies have shown that placebo remedies often work quite well - typically in 30 and often up to 70 per cent of people who take them. It was once thought that the reactions were entirely psychological, built on hope and trust that the healer who gave them the pill was trying to help.

But advances in brain imaging and the understanding of mind-body connections have demonstrated there is a physical element to the placebo effect. For instance, one Michigan study found that patients given a fake anti-pain cream before receiving a mild electric shock to the wrist activated regions of the brain that passed along an expectation of less pain to the actual pain-sensing areas.

Others have shown the pills can regulate heartbeat and respiration, reduce stress hormones and influence the release of brain chemicals.

And a 2010 Harvard Medical School study involving patients with irritable bowel syndrome found that even when they were told they were getting inert pills that were supposed to improve symptoms "through mind-body self-healing process" more than half who got them experienced relief of their symptoms.

While trial by sugar pill was once the gold standard for proving the worth of new medicines, placebos have frequently beat out target drugs for conditions such as depression and anxiety in recent years.

In many cases, researchers think, patients simply believe any pill is likely to make them better. And in some instances, scientists have found that providers working with placebo patients are simply nicer, or provide some additional counselling or monitoring that makes for better outcomes.

One widely reported 2008 survey of nearly 250 Chicago-area internal medicine specialists found that almost half had given a placebo to at least one patient during their careers. Less than 10 per cent said they'd told the patient that the pill had "no specific effect."

Yet professional ethics codes, such as that of the American Medical Association, prohibit doctors from prescribing treatments that they consider to be placebos unless they inform the patient and the patient gives specific consent.

In many drug tests, patients - and often health providers - are not told who's getting what, only that some will get a placebo and some the active drug.

But in 45 trials examined by researchers from the University of Southampton, England, Harvard Medical School and Northern Arizona University, the wording on placebos in informational leaflets did not reflect the new appreciation of what placebos can do, the team reported last month in the online journal PLOS One.

They noted that the target treatment was emphasised as more desirable than the placebo and that target drugs were typically described as "real" or "genuine" while placebos were negatively referred to as "dummy" or "fake."

The leaflets usually mentioned both the potential benefits and adverse effects associated with the target drug, but seldom discussed any potential effects from placebos.

"We believe the health changes associated with placebos should be better represented in the literature given to patients before they take part in a clinical trial," Dr. Felicity Bishop, the lead researcher and a lecturer in psychology at Southampton, said in a statement.

Right now, the placebo effect is largely ignored in patient-information pamphlets, which not only denies patients knowledge they should have, but could also affect results of experiments, the researchers said.

"There is an important issue of consent here: Patients should be fully aware of possible health changes from all treatments in a trial before agreeing to take part," Bishop added.

- SNS

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