One really important point about the placebo effect that a lot of people miss is that a lot of it is not a real physiological change caused by the placebo, but is a result of bias in both the subject and the experimenter. Over any period of time, a person will have a great many variations in mood, pain, etc. (which a subject is able to self-examine), and a great many variations of biological function (which a researcher is able to measure). When those variations correspond to effects that a subject or researcher has been primed to expect, the subject or researcher is more likely to notice that effect. This is simple confirmation bias. If you think trained scientists couldn't possibly stumble on that kind of pitfall, you should read about N-rays[1].
This is just as likely to be true for the "nocebo" effect as for the placebo effect. Dizziness, for example, is a very common symptom for people to experience for myriad benign reasons. Orthostatic hypotension (head rush) is a common cause of dizziness, and it is affected by a lot of minor factors like hydration, vasodilation, how long you've been sedentary, how fast you stand up, etc. This may happen to you three times in a week, and you'd never pay it any mind. But if a doctor told you that a medicine you were taking might cause dizziness, you would notice it.
So to this extent, a placebo (or nocebo) effect can be accounted for with absolutely no "mind over matter" style physiological change whatsoever. It is plausible that some specific placebo effects like reduction/increase of pain response, anxiety, and mood could actually be real psychological effects involving suggestion. But if you hear of a placebo doing something and you think "how could a belief in a placebo possibly have that kind of effect", it's very likely that you are at least partly seeing mere measurement error.
That's interesting but I'm sure it doesn't explain everything. For example pain is actually experienced differently (confirmed by watching nerve pathways light up on fMRI scans) depending on people's expectations. http://www.ninds.nih.gov/news_and_events/news_articles/news_...
I did actually cover that in my last paragraph. There are certain effects that are known to be highly subjective and therefore it is not implausible that a real effect from placebos could be seen, even accounting for biases.
Though I understand that you aren't denying the placebo effect, I'm confused about why you feel that a large amount of the placebo effect is due to bias. After all, most drug trials are double-blinded and placebo controlled, so surely in these trials the placebo effect is legitimate (assuming no scientific fraud).
The placebo is actually there in double-blinded tests to remove any bias and other factors related to the experiment. And no matter how good/legitimate the experiment, any measurement pretty much always causes changes.
The actual effect of the placebo is usually at most a small portion of all the factors that are measured by it. Of course this depends heavily on the experiment in question and some drugs (like psychological ones) have a higher placebo effect than others.
A lot of people seem to have the idea that the placebo effect is very big for medication outside of experiments - but most of the time it's very small to non-existing.
There are complex interactions between the nervous and immune systems.
I don't think that anything has been demonstrated regarding allergies, but I wouldn't rule out a therapeutic effect in this case. The absence of evidence is not an evidence of absence.
I must say I honestly don't know if they were allergies in the medical way. For quite some time I couldn't drink large (>1L/week) of milk while milk products were fine. I always called that an allergy and only learned much later that it's not;)
> I'm confused about why you feel that a large amount of the placebo effect is due to bias
Two reasons: 1) bias is a sufficient explanation, 2) the prior probability for biases effecting experiments is huge, while the prior for beliefs having a strong effect on physiology (with the exception of highly subjective phenomena like pain and mood) is comparatively quite low.
>so surely in these trials the placebo effect is legitimate
It would superficially seem so, but the key point to remember is that cognitive biases are not something we consciously apply. They are instinctive heuristics that worked really well at helping us survive in the ancestral environment (long before the concept of empirical tests), and even when we know about them, we can't turn them off. Cognitive biases work a lot like optical illusions. You've probably seen the checker shadow illusion[1]. You can understand how the illusion works, and know full well that the two squares are the same color, and you can even watch an animation that proves it to you[2], but when you look at the final image, square A will always look darker than square B. Knowing about the illusion doesn't fix it.
So even placebo controlled studies do not allow us to be unbiased in our perception. What they do is allow us to measure the effects of our biases, so that we can compensate for those effects in our calculations.
Not sure I get what you are trying to say here. Are you saying placebo/nocebo effects are real or not?
Using "measurement error" as an argument is kind of insulting to the testers as most of them have got to have a grasp of statistics and other factors in order to publish results that aren't going to get them laughed at by the scientific community.
How do you explain placebo effects in double blind tests?
>Are you saying placebo/nocebo effects are real or not?
It's not a yes or no answer. Part of what we call "placebo effect" is certainly the result of priming and confirmation bias, but for some specific subjective phenomena (like mood), it is plausible that the effect is real.
>Using "measurement error" as an argument is kind of insulting to the testers as most of them have got to have a grasp of statistics and other factors in order to publish results that aren't going to get them laughed at by the scientific community.
>How do you explain placebo effects in double blind tests?
Being aware of cognitive biases doesn't immunize you to them. There isn't even very good evidence that being aware of cognitive biases reduces your susceptibility to them. There is no shame in that, and any scientist who is insulted by the suggestion that s/he is susceptible to biases should go back to Science School. What being aware of biases does allow you to do is design experiments that compensate for those biases.
And that's the whole reason that we have double blind tests. We know that since humans have to administer and participate in experiments, a lot of biasing factors are going to come into play. So we have come up with designs like that which allow us to measure the extent to which the effects we appear to see are due to biases (or the power of suggestion), and how much the effects can be attributed to an actual effect of the drug.
If those are the only two possible answers that you'll accept, he's not saying anything you will hear.
>Over any period of time, a person will have a great many variations in mood, pain, etc.
>When [...] a subject or researcher has been primed to expect [an effect], the subject or researcher is more likely to notice that effect.
>to this extent, a placebo (or nocebo) effect can be accounted for [by these measurement errors.]
>It is plausible that some specific placebo effects like reduction/increase of pain response, anxiety, and mood could actually be real psychological effects[.]
The nocebo effect is quite powerful. I'm 22 years old and was in chronic pain for a year. I had trouble doing simple things like opening doors. Understanding nocebos helped me cure my carpal/cubital tunnel and thoracic outlet problems.
After wasting a lot of money on ergonomic setups and doctors I read Aaron Iba's post on how he cured his RSI [1]. One of my takeaways from subsequent reading and research was that the nocebo effect played a huge role in how I associated computer usage and programming with pain. When you expect an autonomic symptom, you are much more likely to experience it.
Since treating myself with this in mind, along with other techniques such as those outlined by Aaron, it's been a couple months since I've been in pain from using a computer.
Part of this I suspect is that people might already have the symptoms of the side effect but not know it. Almost all of us have random coughs and sniffles and aches and pains, but don't notice them.
Think, for instance, of those times when you've heard a friend or co-worker cough several times over a few minutes and you ask if they are alright, and they have no idea what you are talking about because they were not aware that they had coughed.
When you tell someone the pill they just took might have a side effect of making them cough, they are going to notice those random coughs that they normally ignore, and attribute them to the pill.
In some strange way, the placebo effect has its own placebo effect. People will tend to not voice their issues because they wish to stay on track for their treatment, get out of the doctor's office and on with their life.
After all, a guy isn't going to just blurt out erectile problems if he is led to believe by the expert through the error of omission that erectile problems aren't a side effect. Its just too embarrassing.
The example of the suicide attempt with fake medication causing the subject's blood pressure to drop to dangerously low levels got me thinking.
If the belief that (s)he would die was almost enough to actually kill him/her, would it be possible for someone to end their own life with just their thoughts alone?
Through meditation, people have learned to exhibit some amazing control over things that were thought to be entirely outside of conscious control. Perhaps the best example of this is Wim Hof: http://en.wikipedia.org/wiki/Wim_Hof
That man can spend nearly two hours sitting nearly naked immersed (except for his head) in an ice bath, without his core temperature dropping to dangerous levels and without suffering frostbite. He has also done such insane things as run a marathon in a desert without water.
It certainly seems plausible to me that there are probably many more things that we currently think are not consciously controllable this way that will turn out to be. It would not at all be surprising if one or more of those turn out to be things that you could use to kill yourself.
There really isn't enough information in that anecdotal retelling to make heads or tails of it, but from that limited information, I'd say that person probably just had a panic attack. Panic attacks cause a spike in blood pressure for most people, but for some people the opposite will sometimes happen. I used to have them from needles, and in high school I went to the ER for suspected meningitis. They had me hooked up to monitor my vitals, and when a nurse stuck me with an IV, the room suddenly filled up with panicking medical personnel because my blood pressure hit the floor.
So my guess would be the subject in question took a bunch of pills, freaked out and went to the ER, and then had a panic attack because they thought they were going to die.
But to answer your question, I think that if you can, by panicking, alter your blood pressure (up or down) enough to kill yourself, that just means you had some pretty messed up cardiovascular issues. You wouldn't call that "killing yourself by thought alone"; you'd call it "dying of cardiovascular disease".
I'm not a doctor, but your case sounds more like a vasovagal response than a panic attack.
(I have an interesting vasovagal response -- I can draw my own blood just fine, and a nurse can draw my blood if I don't watch; but I've fainted from watching a nurse draw my blood.)
Interesting. I had not heard of that, and since I have anxiety disorder (I have had panic attacks about other things), I always assumed it was just part of the same thing, and it certainly feels similar. I guess that makes sense given that panic attacks are a feedback loop; maybe the vasovagal response was just a trigger.
I'm not sure about this, because usually when you pass out your "expectations" would stop affecting you much and your normal heartbeat, breathing etc. would resume. I've accidentally passed out from squeezing my vagus nerve, it's not too hard to do http://en.wikipedia.org/wiki/Vagus_nerve but as soon as you're unconscious things generally go back to normal.
If one gave sugar pills to 100 dreadfully depressed patients at their lowest point and claimed it would make their heart stop beating within a few hours. Would any of the patients actually die from believing it? And if an autopsy confirmed the dead patients died from heart failure would the death be ruled a murder, assisted suicide, or suicide?
There is a very old story that my grandparents swore is true.
It's in another language so forgive me for what is lost in translation.
There was a shop owner in the Bazaar who was very miser. One day a lady says 'you are a very miser man, how are you gonna give up your life?' the man jokingly lies down straight on the floor, closes his eyes, and says 'just like this'. And he actually dies.
I think that drug addiction could be partly the nocebo effect. After all, we are told repeatedly as children: beware drugs, because you might find that once you start taking them, you are unable to stop. Then all sorts of terrible things will happen. So for some kids, this may seem like the perfect opportunity! http://AddictionMyth.com
This is just as likely to be true for the "nocebo" effect as for the placebo effect. Dizziness, for example, is a very common symptom for people to experience for myriad benign reasons. Orthostatic hypotension (head rush) is a common cause of dizziness, and it is affected by a lot of minor factors like hydration, vasodilation, how long you've been sedentary, how fast you stand up, etc. This may happen to you three times in a week, and you'd never pay it any mind. But if a doctor told you that a medicine you were taking might cause dizziness, you would notice it.
So to this extent, a placebo (or nocebo) effect can be accounted for with absolutely no "mind over matter" style physiological change whatsoever. It is plausible that some specific placebo effects like reduction/increase of pain response, anxiety, and mood could actually be real psychological effects involving suggestion. But if you hear of a placebo doing something and you think "how could a belief in a placebo possibly have that kind of effect", it's very likely that you are at least partly seeing mere measurement error.
[1] http://en.wikipedia.org/wiki/N-rays