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The Placebo Effect – Once More With Feeling

PlacebosPlacebo is not what you think (MindHacks) is a great article on one of my favourite medical subjects; the placebo effect. It offers a great round-up of the current research into this phenomenon and discusses some possible future changes to its use in a professional capacity.

Given the pervasiveness of placebo success in medical trials, it always surprises me that the use of placebos by medical professionals is explicitly banned (even taking into account the fact that a person in a position of trust would be deceiving you). However, the above article links to an interesting paper written by Adam Kolber – a Bioethics and Law professor, and author of the Neuroethics and Law blog – on the possible ethical use of placebos by medical professionals. Here is its abstract:

Placebo treatments, like sugar pills and saline injections, are effective in treating pain and perhaps a host of other conditions. To use placebos most effectively, however, doctors must mislead patients into believing that they are receiving active medications. While placebo deception is surprisingly common, its legality has rarely been tested. In November 2006, the American Medical Association (AMA) adopted a new ethics provision categorically prohibiting doctors from using placebos deceptively. In so doing, the AMA shifted the legal landscape, making it almost certain that courts will decide that placebo deception violates informed consent requirements.

I argue that the AMA’s new policy is overbroad, insensitive to patient preferences, and likely to have unforeseen consequences. While deception is often exploitative, placebo deception can genuinely benefit patients. Absent stronger evidence to justify a ban than we currently have, deceptive placebos should be treated as scarce medical resources–used sparingly but not categorically prohibited.

One glaring problem with this – no matter how valid the conclusions – is that to use placebos safely and correctly we would need physicians who have the time (and inclination) to thoroughly peruse patient histories – something the overstretched NHS is severely lacking.

On a lighter note, it always amazes me that I learn something new and fascinating every time I read more about the use of placebos. This time my education came from the following paragraphs:

Furthermore, studies done in the 1970s showed that when heroin users inject water (sometimes done deliberately to alleviate cravings when drugs are in short supply), they can experience drug-like euphoria and have been observed to show opiate-like physiological signs such as pupil constriction.

This last point also demonstrates that placebo is not solely about expectancy, belief or ‘being fooled’, as the heroin users knew they were injecting themselves with water. Conditioned responses play a role.

Of course, as with most cases of classical conditioning, this response eventually becomes extinct as the initial stimulus (real heroin) is repeatedly withheld. Still fascinating, though!

(Bonus points if you know why I gave this post its title.)