The placebo effect

[Maciamo]

Medicine in every culture and every age has used the placebo effect abundantly. Hundreds of studies have shown that our mind can be tricked into thinking that a treatment is more effective than it actually is - or just as well made less effective.

In medicine many factors can influence the way a placebo works : the way the treatment is presented (serious, professional-looking, high-tech, "proven to work", etc.), the expectations of others in one's recovery, the reassurance given by the medical specialists, and most importantly the belief and confidence that the doctor and patient have in the treatment.

Placebo could be called "faith healing". In short, it could be said that believing in your treatment, whatever it is, almost always improves the outcome, thanks to the power of the mind alone.

The purpose of placebo is to produce a physiological response through a psychological stimulus.


It might surprise you how many factors are involved in placebo. Ben Goldacre has listed many of them in his book Bad Science. A whole chapter is dedicated to placebo, and numerous references and examples also show up in other chapters. Here are a few examples based on scientific studies cited in the book.

- the colour of a pill influence its efficacy. For instance, stimulants usually come in warm colours (red, orange, yellow), because that it is the natural association made by the human mind with a stimulant effect (tranquilizers and anti-depressants are typically blue or green).

- Likewise the packaging of a medicine, renown of the brand and the marketing campaigns associated to that medicine have shown to increase the efficacy of medicines compared to identical white-brand products.

- new medicines work better than old ones, because of marketing. If a pharmaceutical company advertise an old medicine under a new brand name and claim it to be more effective than the old one, a significant percentage of patients have been shown to lose faith in the older product, with consequence a decreased percentage of people healed. This happened with an ulcer medicine, which cured 80% of the patients in 1975 when it was new, but only 50% a few decades later when it new medicines came onto the market.

- the confidence of doctors in a treatment has a great effect on the patient's recovery. Prescribed the same medicine results are better when doctors say that the drug works very well than when they are sceptical. Yet the medicine is the same.

- alternative medicines, like homoeopathy, acupuncture or hypnosis, rely a lot on rituals to cause a psycho-physiological effect. This is another form of placebo effect.

- many small illnesses can be cured just by reassuring the patient, or by giving them a sugar pill (pill with no medicine in it).

- sham surgeries have been known to ameliorate a medical condition (e.g. knee problem, angina) just because the patients though they had had the real surgery.

- in placebo studies, people told that a specific activity (e.g. cleaning hotel rooms) had a beneficial effect on health indeed became healthier over time compared to the control group that was not informed of such benefits while carrying out the same activity.

- in some cases, doctors have managed to induce the opposite effect of the prescribed pill just by telling the patient that it would have that opposite effect. For example, people suffering from nausea have been made to feel better despite being prescribed nausea-inducing drugs. In other words, a strong psychological placebo can trump the power of an actual medicine.

[donny]

I've been reading very much about the placebo effect and I'll have to admit that I am amazed on how many interesting things I've learned. For me Placebo is just another way for curing diseases.