You are retrieving the silly popular cached belief about the so-called placebo effect.
Perhaps, but the definition of the placebo effect you gave in that link (“every random effect other than that of the active ingredient”) is not what I was referring to, nor is it what I take other people to mean when they use the term. It is possible that your cached belief of what people mean by the so-called “placebo effect” renders you unable to recognise the phenomenon people are talking about. A definition closer to my intended meaning would be something like “the effect caused by the perceptions and expectations of the patient, rather than the particular substance being administered in the treatment”.
My advice to you is to unpack the “doesn’t work” phrase...
Okay, why not? By “doesn’t work”, I mean its effects are the same as or worse than no treatment at all. By “does work”, I mean its effects are more beneficial than no treatment at all. Is that unpacked enough?
...and ponder what kind of study could possibly show that the placebo effect in fact does “work”.
Even if I hadn’t already pondered such a thing (which I had), the link you provided is just such a study. In fact, the conclusion of the study you linked to (very) weakly confirms my belief that the placebo effect works! Their conclusion states:
We found little evidence in general that placebos had powerful clinical effects. Although placebos had no significant effects on objective or binary outcomes, they had possible small benefits in studies with continuous subjective outcomes and for the treatment of pain. Outside the setting of clinical trials, there is no justification for the use of placebos.
When I wrote my original comment I had in mind a particular conversation I had with strangers at the airport. It went something like this:
Bob: My back is killing me. I’ve had two back surgeries and take meds, but it doesn’t really seem to help all that much.
Alice: Yeah, I had that problem for years. I went to [sham-doctor] and received a [sham-treatment] and the pain hasn’t come back since. You should check it out!
Bob: I don’t really believe in that stuff. I thinks its all just placebo.
Me: Placebo or not, she seems to be spending less money than you on the problem and appears to be in much less pain. Doesn’t that mean her placebo is better than your meds?
As for your last piece of advice:
Then exercise your scholarship skills trying to find such a study.
The American Cancer Society (tentatively) explains why the placebo effect works here. Here you can find a study showing changes in the brain chemistry of subjects undergoing a placebo treatment in order to discover the pathway placebos make use of in order to produce their effects. Here is a story about a woman who tracked objective metrics and found large effects from taking placebos (that she knew were placebos). Here is a randomised trial on the treatment of irritable bowel syndrome that found quite large beneficial results from the placebo effect. I could go on and on and will if anyone is actually interested.
My working hypothesis is that IBS is somatisation of mental illness. That could be why the placebo has an effect for it. It’s all in the head to start with. Mental illness and IBS are associated.
Research into the neurological basis of the placebo response was launched by the discovery that placebo-induced analgesia could be blocked by the opioid antagonist naloxone [8]. Today there is converging evidence that opioid receptors and dopamine-reward circuitry form part of the neurological placebo-response pathway [9,10]. With potential mechanisms in sight, the search for genetic bio-markers of placebo response is now a feasible proposition. We recently provided evidence that COMT, an enzyme that plays a key role in prefrontal and mid-brain dopamine tuning, may be a biomarker of placebo response in irritable bowel syndrome [11]
“COMT made for an excellent candidate because it’s been implicated in the cause and treatment of many conditions, including pain and Parkinson’s disease,” says Hall. “It’s also been found in behavioral genetic models of reward responsiveness and confirmation bias, the tendency to confirm new information based on your beliefs.”
Me: Placebo or not, she seems to be spending less money than you on the problem and appears to be in much less pain. Doesn’t that mean her placebo is better than your meds?
Nice. Strikes me as a good example of applied rationality.
Thanks for the links, I’ll take a look in particular at the Benedetti et al. stuff.
The IBS study was already the topic of the previous, linked discussion so I don’t expect to get any more out of it—I’ve already explained why it (and the excerpt you bolded above) are not sufficient grounds for the claim “there is such a thing as the placebo effect”.
Alice: Yeah, I had that problem for years
Has Alice also had two back surgeries? Otherwise, I’d assign more probability to the hypothesis that their differential response to pain meds has something to do with their different medical histories.
A definition closer to my intended meaning would be something like “the effect caused by the perceptions and expectations of the patient, rather than the particular substance being administered in the treatment”.
I find this confusing: in the relevant experimental setups, nobody is directly manipulating (intervening on) “the perceptions and expectations of the patient”. These perceptions and expectations are themselves an effect, usually not measured except indirectly through the patient’s self-reports and voluntarily controlled responses.
What is being manipulated in the studies I’ve seen (e.g. the IBS study) is a specific experimental condition, namely the type of treatment being administered: either a particular substance or a particular therapeutic intervention or gesture.
When people talk about placebo effect, I take them to mean something like “the mysterious healing power of the mind”; that is, they predict that there is a reliable causal effect of holding particular beliefs, other than voluntarily selecting behavioural responses consistent with the beliefs, in particular an amelioration of some pathology or a mitigation of some symptoms. In the IBS studies and in the Dougherty case, the effects observed are all voluntarily selected responses—there is nothing more mysterious at work than the desire to behave or respond in ways consistent with a professed belief.
Ingesting an inert pill (vs a similar pill with paracetamol) doesn’t make my headache or back ache go away, it just makes me less likely to verbally report pain than I would otherwise have. What really takes care of the pain is the paracetamol, and that’s what I happen to be interested in.
Playing games with my own expectations, so as to elicit behaviour that is already under my control, is of limited value—if I want to shut up about the pain, I can just decide to shut up about the pain. (I would predict that a study comparing spontaneous pain reports under differential treatments of “Verbal instruction to suppress pain by not reporting it” and “Administration of inert pill” would favor verbal instruction in a wide range of pain-causing injuries or pathologies.)
Perhaps, but the definition of the placebo effect you gave in that link (“every random effect other than that of the active ingredient”) is not what I was referring to, nor is it what I take other people to mean when they use the term. It is possible that your cached belief of what people mean by the so-called “placebo effect” renders you unable to recognise the phenomenon people are talking about. A definition closer to my intended meaning would be something like “the effect caused by the perceptions and expectations of the patient, rather than the particular substance being administered in the treatment”.
Okay, why not? By “doesn’t work”, I mean its effects are the same as or worse than no treatment at all. By “does work”, I mean its effects are more beneficial than no treatment at all. Is that unpacked enough?
Even if I hadn’t already pondered such a thing (which I had), the link you provided is just such a study. In fact, the conclusion of the study you linked to (very) weakly confirms my belief that the placebo effect works! Their conclusion states:
When I wrote my original comment I had in mind a particular conversation I had with strangers at the airport. It went something like this:
As for your last piece of advice:
The American Cancer Society (tentatively) explains why the placebo effect works here. Here you can find a study showing changes in the brain chemistry of subjects undergoing a placebo treatment in order to discover the pathway placebos make use of in order to produce their effects. Here is a story about a woman who tracked objective metrics and found large effects from taking placebos (that she knew were placebos). Here is a randomised trial on the treatment of irritable bowel syndrome that found quite large beneficial results from the placebo effect. I could go on and on and will if anyone is actually interested.
My working hypothesis is that IBS is somatisation of mental illness. That could be why the placebo has an effect for it. It’s all in the head to start with. Mental illness and IBS are associated.
Nice. Strikes me as a good example of applied rationality.
Thanks for the links, I’ll take a look in particular at the Benedetti et al. stuff.
The IBS study was already the topic of the previous, linked discussion so I don’t expect to get any more out of it—I’ve already explained why it (and the excerpt you bolded above) are not sufficient grounds for the claim “there is such a thing as the placebo effect”.
Has Alice also had two back surgeries? Otherwise, I’d assign more probability to the hypothesis that their differential response to pain meds has something to do with their different medical histories.
I find this confusing: in the relevant experimental setups, nobody is directly manipulating (intervening on) “the perceptions and expectations of the patient”. These perceptions and expectations are themselves an effect, usually not measured except indirectly through the patient’s self-reports and voluntarily controlled responses.
What is being manipulated in the studies I’ve seen (e.g. the IBS study) is a specific experimental condition, namely the type of treatment being administered: either a particular substance or a particular therapeutic intervention or gesture.
When people talk about placebo effect, I take them to mean something like “the mysterious healing power of the mind”; that is, they predict that there is a reliable causal effect of holding particular beliefs, other than voluntarily selecting behavioural responses consistent with the beliefs, in particular an amelioration of some pathology or a mitigation of some symptoms. In the IBS studies and in the Dougherty case, the effects observed are all voluntarily selected responses—there is nothing more mysterious at work than the desire to behave or respond in ways consistent with a professed belief.
Ingesting an inert pill (vs a similar pill with paracetamol) doesn’t make my headache or back ache go away, it just makes me less likely to verbally report pain than I would otherwise have. What really takes care of the pain is the paracetamol, and that’s what I happen to be interested in.
Playing games with my own expectations, so as to elicit behaviour that is already under my control, is of limited value—if I want to shut up about the pain, I can just decide to shut up about the pain. (I would predict that a study comparing spontaneous pain reports under differential treatments of “Verbal instruction to suppress pain by not reporting it” and “Administration of inert pill” would favor verbal instruction in a wide range of pain-causing injuries or pathologies.)