Beef’s Homeopathy thread got me thinking about it and I realize that I don’t think I understand it really. What I think I know is that it’s not well understood, but it’s not really some magical cure to illness, right?
I think that it mostly affects things like perceived pain, but not things like say cancer or actual physical wounds in the body, correct?
I mean let’s say that you have a room full of terminal cancer patients. Cancer is all over their body and they will be dying within a few months at most. NO OTHER treatments are administered, except for playing a mind trick on them. You let them watch what they think is a live broadcast of some doctor on the news claiming to have found the cure for cancer, making it look legit, and then inform the patients that luckily their going to be treated with this miracle cure. how many people in that room WON’T die of cancer?
My understanding is that we don’t understand the physical mechanism that causes the placebo effect. Somehow the nervous system can be convinced to turn off conditions like pain but we don’t understand how.
This is just a wild ass guess, but I’ve always assumed that it works much like hypnosis. Your expectation of a particular outcome allows you to ignore evidence to the contrary and feel as if you are doing better. But I’m pretty sure that even if that is the mechanism in some cases, there are others where it goes deeper. Just like buddhist monks can lower their heart rate or increase their body temperature on demand (as well as a variety of other things not thought to be controlled by the conscious mind), it is possible to have more control over our “involuntary” metabolic processes than we have been lead to believe. The monks can do these things consciously on command. I think the placebo effect gives us a short cut in some instances that lets us achieve similar results without the years of meditation and training.
Whether the placebo effect actually exists is debatable. But for the sake of argument let’s assume it does. The theory runs as follows:
Prolonged stress in mammals is a bad thing. Stress is a prolongation of the flight or fight response. Under conditions of stress your body releases all sorts of hormones that divert blood away from the vital organs towards the muscle, slow digestion, increase blood pressure, prevent rest and inhibit the immune system. Those responses are all very sensible reactions if you are about to be burned to death by a forest fire since they tend to take you out of danger faster. They are terrible reactions when they are prolonged over a period of weeks rather than days or seconds.
The trouble is that humans are just mammals. We evolved from a stock which couldn’t anticipate the future more than a few days ahead and that live din an environment where something was either immediately fatal or it went away after a few days. For other mammals in the wild stress is a non issue because it only lasts a few days and then vanishes.
Humans unfortunately can anticipate the future and when we think we are likely to die or be permanently maimed we experience exactly the same reactions that a deer might feel at the approach of a forest fire. That is bad because unlike a fire the stress of chronic disease is prolonged.
If you believe that you won’t die or be permanently maimed then you naturally stress less. That means you sleep better, you eat better, your blood pressure is lower and your immune system isn’t compromised. It shouldn’t surprise anyone that those things will assist in recovery form illness and injury.
Basically the bizarre behaviour isn’t bizarre for animals with limited self awareness faced with simple problems that can be run away from. Humans are self aware, our problems are complex and we often can’t run away from them. IOW we have both socially and mentally out-evolved our own endocrine system. Given a few hundred thousand years the two systems will doubtless run in synch again, but at the moment we are at the point where one system has evolved faster than the other.
it’s not just Buddhist monks. Anybody at all can be taught to lower their heart rate with about 5 minutes training. Nothing unusual about that. Body temperature I’m ignorant of, but once again I’m guessing that anybody could learn how with just a few minutes training.
There things aren’t under conscious control, for anybody, monk or not. What we can do is use the higher brain centers to modulate the completely unconscious brain centres through a fairly elaborate process involving many intermediaries, but the control remain very firmly within the control of the unconscious. They are only under your conscious control the way that every other human being on Earth is under your conscious control. With some effort You may be able to convince them to do what you want, but it is always imperfect and probe to lapsing once you take your eye off them.
I can’t vouch for this site, but it does seem to give evidence that there must be something more than the patient’s mind involved in the placebo effect. If you induce a placebo effect for morphine when you’re not giving morphine but saline, you can eliminate that effect with a drug that blocks the effects morphine even if the patient is unaware that he is receiving the blocking drug.
Yes, there is some physical effect going on. It’s not just a case of the subject believing their pain has decreased; their pain actually does decrease. And as you indicated, there are drugs which can negate the placebo effect. There apparently is a way for the brain to subconsciously adjust the nervous system to turn down the pain setting.
I do have to say though, I think certain people are more likely to experience placebo effects than others. Many may not experience anything at all.
More than once I received a medication that I really really expected to work, but somehow they didn’t. One was a pain killer, and as far as I know, it was an actual painkiller, but it didn’t do anything to dull my pain.
According to the placebo affect, even if that type of painkiller didn’t biologically “work” for me, it should have at least physiologically.
Have you ever noticed that, if you distract yourself, you don’t hurt as bad? The pain is still going on, as you can tell by stopping the distraction, but you are not as aware of it.
This is what many people thought the placebo effect did–you just didn’t notice the pain that was still there because you believed so strongly that you were being treated. But, if this were the case, one’s belief would not be changed by unknowingly being given a drug that canceled the effect.
To be more precise, it seems that the placebo effect, when the patient believes he is being given morphine, actually does work in the same manner, as something that would cancel out morphine works just as well on the placebo, even if the patient doesn’t know they are taking it.
Absolutely. I’ve had doctors try to fake me out by telling me that a drug was going to have effects A, B and C. I was certainly hopeful that would be true but never EXPECTED any of those things to happen. They never did. When I reported this to them they were genuinely disappointed. I’m sure they were doing it for my benefit and not just to screw with me, but nevertheless, I was immune. In one instance I had to spend several hundred bucks to get a blood test to prove I was taking the meds I was given since one doctor simply couldn’t belief that there was no effect of any kind (long story).
There are objective ways to determine if a person is feeling pain. You can take a person who’s unconscious, hook him up to a monitor, poke him with a pin and you’ll get a reaction.
And as OldGuy wrote, there are drugs that can overcome the placebo effect. Give somebody morphine and they have less pain - I assume everyone agrees this is a real physical effect and not just psychological. But there’s a drug called naloxone that counteracts morphine - if you give somebody nalaxone and then give them a shot of morphine, they will experience any decrease in pain. And this works regardless of whether or not they’re aware of being given naloxone. So again, I think most people would agree this is a physical effect and not just a psychological one.
Now you can tell somebody they’re being given a painkiller and inject them with plain saline and in many cases they will experience a decrease in pain - this is the classic placebo effect. But here’s the kicker - if you give them naloxone with the saline, they will not experience a decrease in pain. The naloxone counteracts the placebo pain-killing effect of saline just like it counteracts the pain-killing effect of morphine. And again, this works even if the person is not aware they were given naloxone.
If the placebo effect was just psychological, the naloxone would have no effect - the person isn’t even aware he received it. The fact that naloxone works indicates that there is some genuine physical change involved with the placebo effect.
My speculation is that that drugs like morphine cause some physical effect in the nervous system that decreases the sensation of pain. And the brain is capable of initiating this same action without the presense of morphine - this is the placebo effect. A drug like naloxone prevents this physical effect regardless of whether it’s caused by morphine or a placebo.
Just some background - apologies for being pedantic.
We have our own morphine - as many here will know - called endorphins. The word is a contraction of the term “endogenous morphine”. Both endorphins and the drug bind to the same receptors. So the most likely explanation for the placebo effect in this example is that the body ups it’s production of endorphins in response to the expectation of less pain. Not really mysterious but still pretty bizarre if you think about it.
Naloxone will block opiod receptors and therefore will block both endorphins and morphine (not positive about that though).
The placebo effect is more of a self-reporting bias than anything. If people expect to feel better, they will - or at least they’ll report that they do.
It’s actually an interesting and complex mechanism. For example, if you give people a syrup that’s supposed to cure a sore throat, and you make it taste bitter and mediciney, they will report having a greater positive effect than if you give them something sweet tasting. If you warn them about the harsh side effects of a placebo, they’re more likely to receive a positive benefit than if you say it’s totally free of side effects. This is probably because it convinces them that it’s really strong stuff, so it must be effective. There are all sorts of quirks that play into people’s expectation with placebos.
This is why most medical testing is done in a blinded fashion with a placebo group. Pretty much any medical treatment that doesn’t totally wreck someone will get a significant fraction of people to report that they feel better, even if the medicine isn’t doing them any good. So basically any medical treatment will result in a certain percentage of people feeling better - to prove that the medicine works, you need significantly more than that placebo percentage. This is also why you get people convinced that accupuncture/homeopathy/crystal healing and whatever else works - they think it will, so they’ll think they’re better.
There’s a Penn and Teller Bullshit! episode that covers this stuff (called Alt Med, IIRC) in a rather embarassing way - they get a guy in a white lab coat to do all sorts of goofy “treatments” to people (including some sort of “sound therapy” which involves him playing a golden kazoo over their sore joints and such) and they all responded positively and claimed it helped.
It’s possible that there’s a psyhiological component at work. I only meant to point out that the key relevance to the placebo effect is in understanding the efficacy of treatments - every treatment is going to have some positive results no matter how baseless it is because people are very suggestable as to their expectations.
If Penn and Teller included acupuncture in their “Bullshit!” then it’s pretty clear they are talking about something that they have made assumptions about without actually doing any scientific research themselves.
It’s funny that you should bring up acupuncture because it’s both a great demonstration of the placebo effect and of the media and public’s misunderstanding of the placebo effect.
A few years ago a pretty big study was done on accupuncture that had three seperate groups of people who had chronic pain. In one group, an actual trained accupuncturist was allowed to do “proper” accupuncture as they normally would. In the second group, untrained people pretending to be accupuncturists stuck needles randomly into the body. In the third group, medical staff used false needles - little devices that pinched the skin to feel like a needle penetration but didn’t actually penetrate.
If proper accupuncture worked, then the first group should’ve shown positive results and the other two not. If the idea of realigning the life force of the person was bullshit, yet actually jabbing someone with needles had some beneficial effect, the first two groups would show improvement but the third didn’t. If all three groups were equal, then it would prove accupuncture is bullshit - nothing but the attention of the treatment and the expectation of getting better would apply.
Well, can you guess the results? Yep, all three groups showed identical improvement. And in a fit of bad reporting and delusion, the media and alt med community actually looked at this as a success! They said not only did the accupuncture groups improved, but even the sham-accupuncture group improved! That must mean that sham-accupuncture is also a working treatment!
What was actually happening of course was an exact demonstration of the placebo effect. All three groups improved because basically anytime they get a treatment that the expect to work they’ll feel better. If accupuncture actually worked, you’d see the group that got real accupuncture improve more than the group that received sham accupuncture. This is the very essence of the placebo effect, and yet the public perception of that study was that it somehow supported accupuncture when it very clearly debunked it.
These are the conclusion that can be made:
Group 1 - Either acupuncture worked or the placebo affect caused the changes
Group 2 - Either acupuncture (but not done properly) worked or the placebo affect caused the changes
Group 3 - Either skin pinching works or the placebo affect caused the change
Unfortunately the groups are independent and you really can’t conclude much, could be the placebo in all 3 cases or it could be something about the “treatment”.
However, if you read the articles I linked to, there you have studies that are looking at molecules and brain structure. In those cases it’s a little easier to conclude that there is a physiological change.
What you will notice in the second study is that they used lasers that gave no sensation to the participants to avoid the placebo affect.