Thursday, 27 February 2014

BBC Horizon - the power of the placebo

This season of Horizon has been a really strong one and "the power of the placebo" was no exception. The show not only established that the placebo effect works but that it can have genuine physiological effects. Fortunately they don't go into how a sugar cube has some kind of quantum channelling effect where it transports your mind to the memory of a pain-free life but rather how our brains respond to being fooled into thinking the placebo has a physiological effect.

I think a lot of people think mistake my scorn for homoeopathy and alternate therapies as me thinking they don't work. That's not the whole truth. I totally believe these things can have a placebo effect on certain individuals - I'm just derisive of the possibility the water/healing hands/positive sunbeams in themselves work. A bit like thinking the spoon itself is responsible for the taste of the pudding that's on it (best analogy I can think of on the spot).

Anyway, the show gives us a couple of examples from placebos that enhance physical performance and suppress pain to those that can alleviate symptoms of Parkinson's disease. There's even a case where a fake surgical procedure works! The show then discusses how the placebo effect might work. In the case of pain/Parkinson's it seems that your brain releases opioids/dopamine that achieve the desired relief in of itself.

As an aside this made me wonder about a couple of things. Does this mean the placebo effect doesn't work on animals (I'm guessing it shouldn't - are there any homoeopathic animal testing results?). Assuming it doesn't work on animals then does this mean that the human mind is powerful enough to self-medicate/overcome pain? This was my initial thought but then I flipped and thought "maybe animals can do this all the time?" I have a feeling they probably can as it seems like a useful skill. Maybe our problem is that we've forgotten how to do it or our consciousness (assuming we have a higher level than that in other animals) over-rides such a basic function. A lot of "ifs" there and maybe some digging around will provide some answers.

Back to the show. Another snag I've always held with the placebo effect is that surely it stops working once you explain how it works? You couldn't give tell someone you were giving them a sugar pill and expect it to work, surely? Well, apparently you can - the show stated that in one study, 63% of people found the sugar people worked despite knowing it was a sugar pill. I find that pretty staggering. This segment of the show also had one of the funniest moments where a patient in an attempt to get more placebo pills went to a pharmacist and asked for some (I'll let you unravel the layers of why that's so funny).
An even more extreme example was a guy who was hypnotised in order to have his wisdom tooth removed without anaesthetic. The placebo may have worked for him but my teeth ached on his behalf having to watch the scene. I'm pretty sure there's no way someone could fake that as he'd have twitched at the intense moments of pain?

So how on earth can a placebo work when the patient is fully aware they are being fooled? It seems that the Doctor/patient relationship is key - by building a level of trust between the two, the Doctor can still cause the patient to feel better. It's probably one of the reasons the NHS tries to extend consultancy times.

Like all good documentaries it left me with several other thoughts and questions, such as;

  • can prayer achieve similar affects when directed towards healing? 

  • If the placebo effect works then surely it must mean that drugs that perform better than the placebo control are STILL better? Although I suspect medical testing has concocted controls to overcome the placebo effect (possible follow up for control freak there)

  • can the placebo effect be transferred from one human to another? eg if person "a" believes person "b" is getting better does person "b" start to show genuine improvement? I'd guess if person "b" knew that person "a" was thinking then it could well work.

  • and, on a rather sinister note, is the opposite true? If you think you are being poisoned or are in more pain can the placebo effect induce changes that make this so? I don't see why not. If so, then this should also be taken seriously - especially if it can be transferred from person to person eg you could have something similar to Munchhausen's syndrome just by a parent believing their child is sick - without the parent doing anything to actually make the child ill. Scary stuff 
See, I told you the show induced lots of wacky thoughts. Job well done, Horizon!


  1. Bottom point - yes, it's called the nocebo effect.
    Top point - complicated. From what I recall, the major study into intercessory prayer actually had those who knew they were being prayed for (the 'treatment' group) doing worse than the control - maybe due to pressure to get better?!

    1. Apt name for the anti-placebo.
      That's interesting in terms of prayer - it really does suggest that the relationship between the subject and administrator is an important one. I guess if a drug doesn't work you don't feel like God is rejecting you!

  2. A point against purely placebo drugs (ie they work, albeit only through the placebo effect), is that "real" drugs should have both the pharmacological effect AND the placebo effect, so they should always be better.

    1. That's a great point/definition. I hadn't thought about that but of course the actual drug should carry the placebo effect with it as a baseline. Thanks for the useful thoughts :)