A placebo usually has a positive effect in about one-third of all participants on average-suggesting that it's down to wishful thinking-so any reported improvement in participants over and above that pro-portion must be due to the actual drug.
This type of study is known as the 'double-blind placebo-controlled' trial because neither the participants taking the pills nor the medical staff giving the pills know who is taking the real drug.
As this 'blindedness' supposedly eliminates any biased results, this sort of trial is officially viewed as the 'gold standard' for drug testing.
But suppose this isn't the whole story. Could it be, for instance, that the mind is the active healing agent whether the participant is given the real drug or a placebo?
Mind or medicine?
A research team from Harvard Medical School have challenged the double-blind model and come up with startling results that question the effectiveness of the drugs we're given (PLoS ONE, 2010; 5: e15591).
The Harvard researchers, led by professor of medicine Ted Kaptchuk, who has a special interest in the placebo effect, decided to put a spin on the double-blind trial by telling the participants that they were taking a sugar pill-and the pillbox they came in had the word 'Placebo' emblazoned across it-and that the pills contained no active medication. They were also told that "placebo pills, something like sugar pills, have been shown in rigorous clinical testing to produce significant mind- body self-healing processes".
To see if this 'unblinded' test made any difference, they divided a group of 80 IBS (irritable bowel syndrome) sufferers, giving half of them a placebo-and telling them so-and the rest nothing (the control group). They all had chronic IBS with severe symptoms.
After three weeks, the placebo group not only reported improvement in their symptoms well beyond that of the controls-although some of the non-treated controls reported some easing of their symptoms, too-but
it was also clinically significant. In other words, the placebo had the same positive effect as a powerful IBS drug.
A recent study of the IBS drug alosetron found that 51 per cent reported "adequate" improvement in symptoms (Clin Ther, 2008; 30: 884-901), compared with 59 per cent of Kaptchuk's group-even though they knew they were taking a sugar pill.
The healing mind
So how did this happen? Kaptchuk and his team believe a number of elements were at work, and all served to boost the healing power of the mind.
o There was a "warm" relationship with each participant, and all were given the time to talk about their condition. Several participants said that the therapists who inter-viewed them were concerned about their problem and were
kind (a word that was underlined by several patients). This could explain why even those not given the placebo also reported improvement in their symptoms.
o Even though the group knew they were taking a placebo, the numbers who benefited were far higher than in the usual placebo-controlled trial, where they don't know what they've been given. Kaptchuk believes this is because the group knew they were getting a treatment 'of interest', whereas the subjects of most drug trials know they have only a 50-per-cent chance of getting it.
o Although participants knew they were given a placebo, the initial ads to attract volunteers described the study as an intriguing mind-body intervention. They were also told during the trial that the placebo had mind-body self-healing qualities. This may have put the idea into their head that a placebo has healing powers, helped by the fact that they were told this when they were given the pills.
In an interview afterwards, Kaptchuk said, "These findings suggest that rather than mere positive thinking, there may be significant benefit to the very performance of medical ritual."
Critics may still argue that the results were based only on positive thinking or on subjective measures of pain, but Kaptchuk points out that, in fact, many 'scientific' drug trials rely on nothing more. Many diseases, such as depression and chronic pain, for example, are ultimately based on subjective assessments, and drug manufacturers consider these to be valid outcomes.
Yet, 'medical ritual' can have a physical impact as well, as researchers discovered when they tracked the progress of 83 rheumatoid arthritis patients who visited a homeopath.
They found that the consultation itself-rather than the remedy-was making the difference. After consultation, patients reported physical improvement in their swollen joints, and a decrease in their pain and negative feelings (Rheumatology, 2010; doi: 10.1093/rheumatology/keq234). In other words, a long talk with a sympathetic practitioner brought about physical changes.
Placebo-response levels in the usual drug trials are often between 30 and 40 per cent, the same ratio as those who report improvement in symptoms. Researchers look for only a few percentage points more in those given the real drug, and consider this enough to demonstrate that the pharmaceutical agent is effective.
Sometimes, however, the placebo-response levels are on a par with the active drug, even one that is well established and has been in use for years. This was discovered when analyzing 32 studies of various anticholinergic drugs, prescribed to treat patients with an overactive bladder. This condition affects one in six adults-and far more among the elderly-and its symptoms include a sudden urgency to urinate, urinary incontinence, frequent urination and nocturia, a need to urinate during the night.
When researchers at Otago University in New Zealand reviewed the results of studies where a drug was pitted against a placebo, they found no differences in terms of benefits. The placebo was every bit as effective as the active drug. The only difference was that the placebo didn't come with a host of side-effects, which included dry mouth and eyes, constipation, headache and nausea.
The studies were all double-blind, so neither the participants nor the medical testers knew whether they were being given a placebo or the drug (BMJ, 2003; 326: 841-4).
Is it all placebo?
So what happened? The process itself appeared to be the point, as also demonstrated by the Kaptchuk study. The sympathetic ear, kindness and a show of concern, and the ritual of being given and taking a pill-all apparently worked together to activate the healing abilities of the mind, as though we have innate abilities that need 'permission' from an authority figure to blossom.
If so, then all of medicine is a placebo.
WDDTY VOL. 21 NO. 11