In part 1 of the series I brought up placebos briefly and I promised you more. It’s important to discuss placebos because many successes of health products and interventions that are not supported by the medical community can at least be attributed in part to the placebo effect. Your brain is a powerful machine and the effects of the placebo can be extremely convincing. Here are some interesting facts about placebos:
1. Placebos can be somewhat of a self-fulfilling prophecy: if someone is told a placebo acts as a muscle relaxant, their muscles actually relax.
2. For some conditions (such as mild depression, or some coughs), placebos work just as well as drugs with active ingredients.
3. Rats experience the placebo effect.
4. The placebo effect can work even if the patient is told they are taking a placebo (but keep in mind: in this kind of trial, it’s impossible to blind the participants!).
5. The placebo effect works better if the intervention is more invasive or severe. The placebo effect is stronger and works on more people when a fake drug is injected with a needle than when it's simply swallowed in pill form.
6. To properly control for the effect of certain surgeries, clinical trials are sometimes conducted with a group receiving a sham (fake) surgery. The ethics of doing this are often debated (your thoughts in the comments!).
7. Pills with a visible, well-known name brand work better than pills that look generic.
8. The placebo effect can work in reverse: if given a placebo and told it will produce negative side effects (like headaches), nearly 1 in 5 people will experience those side effects. This is called a nocebo.
9. The color of placebo pills matters: “hot” colors like red and orange work better as stimulants, and “cool” colors like blue and green pills have a tranquilizing effect.
10. In some countries, doctors can prescribe placebos. A common use case? Placebo antibiotics for… viral infections*!
Flaten MA et al. (1999) Drug-related information generates placebo and nocebo responses that modify the drug response. Psychosomatic Medicine 61(2):250-5.
Pittrof R (2011) Placebo treatment in mild to moderate depression. The British Journal of General Practice 61(584):222.
Nolan TA et al. (2012) Placebo-induced analgesia in an operant pain model in rats. Pain 153(10):2009-16.
Kaptchuk TJ et al. (2010) Placebos without deception: a randomized controlled trial in irritable bowel syndrome. Plos one 5(12):e15591.
Kaptchuk TJ et al. (2006) Sham device v. inert pill: randomized controlled trial of two placebo treatments. British Medical Journal 332(7538):391-7.
Dowrick AS and Bhandari M (2012) Ethical issues in the design of randomized trials: to sham or not to sham. The Journal of Bone and Joint Surgery 94(suppl 1):7-10.
Branthwaite A and Cooper P (1981)Analgesic effects of branding in treatment of headaches.British Medical Journal 282(6276):1576-8.
Rosenzweig P et al. (1993) The placebo effect in healthy volunteers: influence of experimental conditions on the adverse events profile during phase I studies. Clinical Pharmacology and Therapeutics 54(5):578-83.
de Craen AJ et al. (1996) Effect of colour of drugs: systematic review of perceived effect of drugs and of their effectiveness. British Medical Journal 313(7072):1624-6.
Hrobjartsson A and Norup M (2003) The use of placebo interventions in medical practice – a national questionnaire survey of Danish clinicians. Evaluation and the Health Professions 26(2):153-65.
*Avid Scientific Chick readers will know that antibiotics cannot treat or cure infections caused by viruses.