Most adults are aware of the placebo effect, where the belief in some medical benefit can enhance that effect. But few know that there are twists to the placebo effect that have a significant impact on drug testing. It is the existing ‘gold standard’ drug trial, as characterised by the following main attributes, which is impacted:
- One set of patients receives no treatment.
- A second set of patients receives the drug being tested
- A third set of patients receives a sugar pill (placebo) that looks like the drug
- The trial is double blind – neither the patients nor the administers of pills know who is receiving the drug or the placebo
- The trial is randomised – the patients are randomly assigned into these groups
The key to the double blind aspect is that patients should not be able to differentiate between the placebo and the drug. Recent research with anti-depressant drugs showed that this is not always the case. It appears that many patients were able to work out if they were receiving the drug, because they could detect the side-effects of the drug. They could sense that they were taking an active substance as opposed to a placebo pill. Research was carried out to try to cancel this detection process by using an alternative drug instead of an inert placebo tablet. The drug would be one that generates similar side effects to the drug under test, but not any anti-depressant effect. The net effect was that the drug was no longer demonstrably more effective than placebo. Minimising the flaw of drug detection (that had negated the vital double blind aspect of drug testing), showed the drug to be much less effective as an anti-depressant.
To explain this, it appears that by being able to detect that a drug rather than placebo was being administered, the patient’s expectations of healing would be elevated. Conversely, a patient that knew he was taking a placebo would have a reduced expectation, and hence lowered placebo effect. There is a profound conclusion to be drawn from this: that drugs shown in scientific studies to outperform placebo may actually have been operating by virtue of the placebo effect in addition, or in place of any biochemical effect. The existing gold standard drug trial is not as sound as it is made out to be.
There is another twist to reveal, courtesy of ‘New Scientist’ magazine. Researchers discovered that the effect of the anxiety reducing drug Diazepam virtually vanished when it was administered unknowingly. Likewise, it was discovered that morphine could be provided at fairly high levels to patients in pain with no effect on that pain if administered without the patient’s knowledge. This too was a telling discovery. Morphine is an extremely well established and effective treatment for pain, effective in most people. Yet, it seems, a part of this very efficacy is due to the placebo effect. This links in well with the placebo detection problem – anti-depressant drugs being barely any more effective than placebo when the placebo used was indistinguishable from the drug. Continue reading →